SUBSTRATA – Morphology of the ancient city, beyond its ruins
by Giuseppe Strappa
in U+D Urbanform+Design n. 9/10 – 2019
- The issue
As part of the efforts we have been making for years now to renew the research methods used in the field of Urban Morphology, I believe that we shouldn’t limit ourselves to considering new topics; rather, we should take a fresh look at the matters with which the process-based school has always traditionally dealt (STRAPPA 2018). For example, we should review the ancient origins of many modern-day developments: the foundations, the material sediment and deposits of memory upon which we have built and that we use to build.
The morphology of the built environment is not a soulless discipline. We must have imagination, we must take the powerful and mysterious ancient deposit that underlie our architectural work and give them a synthetic form. This ancient layer is not dead: its living nature manifests itself through the changes that it causes, above the archaeological level, in the materials and shapes that are reused in construction or in our consciousness. It is because of this, of its generating power, that we cannot allow ourselves to merely examine it using the tools of mere perception that often lead us to create a myth around the Ancient based on its distant splendour.
Instead, we should reconstruct its developmental process in order to understand its living substance, using reason, because experience – our direct, concrete relationship with things – cannot but be partial and therefore misleading in this case. We need to make renewed efforts to distil the information at our disposal.
Despite the repeated affirmation of the principle of continuity between modern cities and their historic fabric and the definition of the Middle Ages as a time that was not at all a step backwards compared to ancient times, in actual fact the archaeological part of cities is still interpreted as a legacy of traces and foundations imparted to newer buildings in an episodic way, without the use of a general method that can condense multiple aspects into one single unified interpretation. ‘Unified interpretation’ does not mean recognising ancient remains in the appearance of modern cities, a field of study that, as we all know, has produced a quantity of researches, often with significant results. Instead, the term wishes to highlight how some tools used in morphological investigations of the built environment mostly limit themselves to considering the late medieval period, when going over the phases that lead back to its matrices, without systematically tracing them back to what generated the forms of its buildings and cities using the concepts of organism, process and type. Equally, the process through which ancient matter becomes material and turns into parts of new organisms, or the way in which spolia have been recognised as new elements to be reused, have not led to a truly systematic investigation in the field of urban morphology. This is true, at the same, when it comes to development processes considering the primary dwelling types, where, at least in Italy, we have gone no further than the housing type with external profferlo staircase. Where do these types come from? What did the ‘second nature’ of ancient ruins create? How was it used to expose the cryptae that could be inhabited, how did it generate the basic domus terrinea, and as a result the domus solarata, essential steps in growing complexity that led to new forms of dwellings (HUBERT 1990), not to mention the medieval palatium, domus maior and turris as the dawn of a new form of public building that developed in the late14th century (STRAPPA 2015)
Imperial age fabric in the Trastevere area (MURATORI 1963).
Overlapping of the medieval fabric (V-XII century) to the imperial age substratum in the Trastevere quarter after the phases of urban contraction (V-VII century), evident in the abandonment of the southern part of the pre-existing fabric, up to the late medieval reorganization processes and recasting of the previous structures during the growth phase of the XI-XIII centuries (MURATORI 1963)
Imperial fabric of insulae along the Via Recta, with indication (B) of the area of Palazzo Lancellotti, formed recasting row houses generated by the consumption of insulae (MURATORI 1963)
Formation of block B of the previous plan in the reconstruction of Gianfranco Caniggia. From above. Current state, where the substrate cell of the ancient fabric is recognizable. Block substratum formed by elementary cells arranged around the open court space. First consumption phase of the ancient substratum with the reuse and superelevation of the substrate cells (CANIGGIA 1963)
It is a process in which it is often impossible to detect the intangible aspects imparted by the substratum (forms and their types) and the physical and tangible aspects (matter and materials). Perhaps the perfect example of this are the objects produced during the long artistic life of the Cosmati family, who not only used marble and stone from ancient monuments from the 12th to the 14th centuries, but also ‘created’ forms and patterns from them for mosaics, ambones and floorings. The same consumption of the ancient city’s form also began with its self-destruction: ‘…in a certain sense we may say that the history of the destruction of Rome begins with the reign of Augustus, who undertook to transform the capital of the Empire from a city of bricks into a city of marble’ says Lanciani (LANCIANI 1901),quoting Suetonius (‘Marmoream se relinquere, quam latericiam accepisse’). Therefore the oldest substratum that has disappeared can only be understood through the form it created: it is a morphological problem and it can be tackled by turning to the notions of organism and process.
Gianfranco Caniggia raised the issue with his seminal study on the city of Como, which he used to build up a method of interpreting the change from a domus to a modern residential organism using type-based phases: ‘tabernisation’, infilling, development from single-family to multiple-family house (CANIGGIA 1963). In the same years that Saverio Muratori listed the criteria to be used when examining the cultural characters that make up the built environment (rational-cultural, economic-technical, ethical-political, aesthetic-historic), identifying four different ages of change, of which no less than two (Royal – Republican and Imperial) concern the development of the ancient city. Muratori was particularly referring to Rome(MURATORI 1963), though it is well known that he believed that the method he proposed was generally valid (and it is in keeping with that spirit that the comments we will make on Rome should be understood, in the wake of his guidelines). Studies concerning existing city layouts outside Europe, for that matter, have shown how an analysis of the historic layers proves to be an important resource even in areas that are culturally very different (WHITEHAND 2016).
I believe that we should keep these precedents in mind so as to rebuild a scientific understanding of the way in which the layered forms of history have been transmitted to modern cities. Or rather, of the way in which modern cities have interpreted ancient forms: not the city of Alberti, Palladio and the other treatisers who reverentially approached the legacy of the past to create a learned architectural language, rather, the city where a distant basis of matter allowed the concrete reinvention (the rediscovery) of everyday architectural ‘speech’.
I think we should start by attempting to talk less of ruins. The term is as romantic as it is overused, from the picturesque explorations of the Grand Tour to contemporary revisitations, to the point where it has exhausted the possibility of proposing definitions useful to morphological studies. I think the most appropriate term we should assume (STRAPPA 2015) is substratum.
5. The Pompeus Theater in the reconstruction of Rodolfo Lanciani, s.d. (Gatteschi coll.)
6. Fabric formed by the consumption of the Pompeus Theater (surveys by Centro Studi di Storia Urbanistica, 1962)
Unlike a ruin (from the Latin ruere, to collapse), a substratum (from sub sternere, to spread beneath) is recognised as a beginning, the living basis from which new organisms can spring. It is the part underneath the current built environment that no longer has any purpose but can nevertheless contribute to the life of new fabric, creating up to date building types: the distant and fertile foundation that gives rise to a new organism. We cannot, anyway, reduce the complexity and richness of our ancient heritage to universal interpretational patterns that classify types and processes in a kind of taxonomy of the Ancient. That is true for any built environment. Instead, the identification of a few common criteria that allow us to interpret these phenomena through an architect’s eyes, tracing the many outcomes back to the general rationales that produce them, can prove useful to morphological studies.
From this point of view, we can define a ‘substratum’ as the combination of elements that once belonged to a building organism which, despite having lost both their the relationship of necessity that bound them together (their purpose and original organicity), and the continuity between the different phases of change and development, still nevertheless tranfer specific characters to the buildings springing from them . The set of these characters, transmitted in a typical and recurring form, can be defined as a ‘substratum type’.
When ancient organisms are practically reused with a new function (such as the churches of Santa Maria ad Martires, Santa Maria degli Angeli or the Pantheon),we cannot properly talk of a substratum type. Instead, the domus becomes a substratum type when it breaks up into ‘pseudo-row houses’, single-family single-facade houses aggregated around the space of the atrium that becomes a public area. Similarly, the orrea and portici structures become the substratum type of nodal public buildings when the central courtyard becomes the node, the main inner room (served, supported, central) of the new layout through a ‘knotting’ process.
The analogies with linguistics are evident, a discipline where ‘substratum’ is understood as the layer that precedes and influences the overlapping of a new language, as occurred, for example, with Etruscan and Latin or the Celtic and English. However, we should note how the term, when used in architecture, indicate the basis of an action. It implies the presence of critical consciousness, the ability to interpret and choose and, therefore, an identification of what has already been given, of what ‘lies beneath’: i.e. the sub-stantia, the substance, the essence of a thing.
This term therefore not only contains the notion of rootedness and transmission; it also refers to the means, the tool we can use to reach the essence of form, of its universal being. This universality, a quality that the actual building did not possess due to the very fact that it was constructed, constitutes a fertile abstraction: an identification as well as a design, the way in which we give a new unity to the multiple and scattered forms of the remains we have inherited. It was, furthermore, an idea rediscovered thanks to the medieval revival of the metaphysical Aristotelian concept of substratum. In other words, it is a design action, as demonstrated by the possible allotropic forms derived from the interpretation of a single substratum. Proof of this is the built environment, the way in which the material legacy of an ancient, multifarious and composite city was interpreted in a unified way by the new buildings erected in the late Middle Ages, in accordance with a particular design idea of the Ancient that surmised the existence of an original, primary substratum we can trace. It is a kind of matrix of the forms the past imparts to us, the πρῶτον of the Stoics you might say, or even the common original substratum of the universe, the primary layer that binds all things, a common idea in the early Middle Ages that Solomon Ibn Gabirol attempted to translate into a theory. It is then that we grasp the new, general meaning that this definition involves: every construction, at any scale, is an invenire, a finding and an invention; all fabric is a reconstruction, every building a rediscovery.
A new city’s formation, therefore, occurs with the recognition of older building organisms, what can be described as pre-formed matter that already possesses a form of its own, placed at the end of an entire life cycle and the beginning of another. I believe we can usefully distinguish two different processes in the tangibly continuous formative phases.
- The first, the consumption process, consists in the use of buildings that make up the urban organism until the original features (constructive, distributive, spatial) belonging to their type are lost. In this sense, the substratum is an advent that marks a phase of crisis, the start that establishes the initial structure of things; or rather, can establish it, because it is obvious that the concluding phase of consumption introduces a pair of opposite, yet complementary concepts: the essential concepts of cancellation and duration that we cannot go into here. Nevertheless, the consumption of the Ancient is never in itself a dissipation, it is not due to the mere economic necessity of avoiding the importation of materials from outside of the city. The heritage is always considered to be too precious to be squandered, even in periods of great poverty and distress. Just take Abbot Suger’s plan to transport the gigantic columns found lying in the Baths of Diocletian to Paris, considering the economic and technical conditions of the early 12th century, so as to use them in the reconstruction of the Basilica of St. Denis. Apart from that, even as far back as the time of Theoderic, the symbolic importance of Roman antiquities was so great that the enormous effort of moving columns from the Domus Pinciana to Ravenna was considered justifiable (GNOLI 1971).
- The second, the layering process, involves the diachronic development that lays down consecutive strata, each of which inherits features from the previous one and transmits others to the next. This phase continues until a new building is constructed which, over time, is also destined to contribute to the layering process. In this sense, the architect’s work contain an its own hermeneutic centre, which consists in searching for the general latent design, using the particular traces left behind by the consumption process (STRAPPA 2018). A latent design that is valid even in its contemporary condition.
It is worth stressing, by the way, how it is not easy today to propose a working method that starts from the particular and works towards the general, towards the abstraction. It is no coincidence that this work, which lies at the heart of every architectural theory, has been generally abandoned by Italian faculties of Architecture.
7. Umbertino-age consumption of the Terme di Diocleziano exedra. The new urban pole orients the fabric based on the Via Nazionale restructuring route, which is superimposed on the ancient one oriented by the Vicus Portae Quirinalis
it is worth highlighting that we can detect two essential principles at work in both phases.
- A principle of belonging whereby each substratum has its own predisposition towards a form and every form contains its own substratum. This principle, whereby the new form and substratum belong to each other in a reciprocal relationship, can be applied in general, and to design in particular, as the concept of substratum can also be applied to the combination of intangible contributions (which are intrinsic to a civic community, to a particular historical phase or a cultural area) and are realized (becoming reality) thanks to the concept of type. In the case of cities founded on ancient remains, the substratum physically transmits its layout (its way of providing a single, shared form) to the new buildings. Take, for example, the many redevelopments that took place in Rome after the unification of Italy, such as Piazza della Repubblica, which completed the transformation process of the ancient structures that began with Michelangelo’s conversion of the the basilica hall in the Baths of Diocletian, then redefined at an urban scale by the conversion completed in 1898 by Gaetano Koch, including the remains of the Baths exedra and preceding the axis of Via Nazionale.
- A principle of organicity, whereby the substratum generates a modular series network that sometimes reflects the original hierarchy, but at times overturns it, as has often happened to grand complexes, particularly those dating from the imperial age (take, for example, the Theatre of Pompeus or the Balbus Crypt), giving rise to new basic buildings (houses), creating typical proportions that elsewhere are linked to the land partition, which here are linked to proportions identified in ancient structures. As far as the urban fabric formed by base buildings is concerned, we can clearly perceive their organic modularity (when we are not dealing with the consumption of public complexes), mostly derived from buildings such as insulae, apartment houses for rent, consisting of groups of rooms, usually square of around 4/6 metres per side, distributed by balconies, sometimes over six storeys high and partially built in wood when it comes to the upper floors. The characters of this type of housing demonstrate the organicity of the transformation process. Indeed, they accounted for most of the ancient fabric and had even greater influence than courtyard houses in forming the medieval fabric. In Constantine’s era, the Curiosum Urbis Romae Regionum XIIII only lists 1,790 domus, which were probably still single-family dwellings, compared to the 44,300 densely inhabited insulae that occupied the large swathes of land set aside for multi-family house for the poorer classes(LUGLI, 1941). The insula, as a physical manifestation of a building type, was to disappear during the Middle Ages in Rome, leaving an urban network that was potentially open to an infinite number of interpretations. Nevertheless, it is worth noting how the almost total desertion of the city did not actually constitute a clear historical break as regards subsequent phases. The skills that were to be rediscovered inherited most of the ancient knowledge, albeit in new terms. For example, some features of the insula were transmitted to subsequent buildings, particularly construction features (such as the vaulted roof of the ground floor ceiling and the wooden ceilings of other storeys) or the connection between houses and shops (taberna), often consisting of a sales area with a mezzanine living space, as in late medieval shops that inherited the size of the elementary cell from the insula. These ancient base buildings were built in modules along routes that were to be inherited by the later medieval city and transmitted to modern one, starting from the urban penetration of territorial roads, such as the Via Flaminia which led to the Via Lata. We can see the same modularity in the buildings appearing along other roads derived by the permanence of planned axes that continue to connect large urban polar areas, such as the Via dei Coronari, which continues to orient the structure of Rome’s urban fabric from Via Recta to the east up until the Pons Neronianus to the west, from the Tiber to the north until the Circus Flaminius and the Porticus Pompeianae to the south, with slight twists and turns, beyond which the fabric is oriented by the roads (particularly the Via Triumphalis) that connected the Forum Holitorium, emerging from the ancient river ford of Tiberina Island to the great porticoed buildings (Minucia, Octavia, Gallatorum) and the Theatrum Marcelli in Pons Neronianus (CATALDI 2016). Or such as the roads of the Trastevere district, which are not only based on the territorial route of Via Portuensis, but also on the axes of the Aurelia Vetus, determined by the Pons Aemilius to the east and the AurelianGate to the west, and by Via Septimiana, which linked the focal point occupied bythe Meta Romuli and the Circus Neronis (which was to create the Vatican complex) to the area where the complex of Santa Maria in Trastevere, a new pole of the city beyond the river, was to develop.
When it comes to ancient building types, moreover, their particular characters in themselves allow for a myriad of different outcomes from medieval renovations. Muratori wrote: ‘[Imperial] building types are easy to adapt to a number of functions thanks to the serial layout of porticoes and tabernae and the courtyard layouts arranged on the constant structural lines of later insulae’ (MURATORI1963). A perfect example is the evolution of the Basilica of San Clemente, which reached a stage in morphological maturity during the XII century, in which the geometric importance and proportions of the serial rooms of the buildings dating from the Flavian era were unified within the hierarchy of its aisles. The intermediate Paleochristian church, which was in direct contact with the ancient substratum and upon which today’s church was built, identifies a building type that was to be developed throughout the V century, updating the proportions of the aisles (narrower, longer, higher), whilst maintaining the essential characters of the original basilica (KRAUTHEIMER 1986), proof of the long morphological life of the remains buried under the new buildings. Another good example is the Church of Saints Cosma and Damiano, built using the remains of the southern part of the Basilica of Maxentius as early as the first half of the V century.
Sometimes the ancient matrices are influenced by the changed alignment of the new layout, as in Santa Maria in Cosmedin. Other times, it is the past of previously existing colonnades that almost directly transmits the old modularity to the new organisms above it, as noted in a large number of Roman churches, such as San Nicola in Carcere at the Forum Holitorium, built on top of the peripteral temple of Juno Sospita. We can also surmise that the modularity of the substratum was transmitted to new buildings even in less obvious cases, such as the III century colonnaded organism (perhaps a civic basilica) that imparted its proportions to the church of San Martino ai Monti, which was partly built reusing ancient materials, or as in the remains that were definitely still in existence in the V century on the Mons Superagius in the Esquilino area, left behind by a large courtyard building (perhaps the Macellum Liviae) when Sixtus III built a basilica that reused 42 old columns, imparted to subsequent renovations that later gave rise to Santa Maria Maggiore, completed by Ferdinando Fuga’s facade. It is a modularity that the substratum sometimes imparts in complex forms, such as in the Savelli buildings on the Marcellus Theatre or Palazzo Massimo on the Odeon, or the various buildings of the Insula Mattei that were built on the area of the Balbus Theatre, which were forced to deal with the difficult geometric influence of the radial substratum below them.
8. Basilica of San Clemente. I-III century AD substrate consisting of a special serial building, perhaps belonging to the ancient mint and then to a Christian community center (KRAUTHEIMER 1986), formed by serial rooms organized around an open courtyard.
9. San Clemente. Early Christian IV-XI century basilica, obtained by "knotting" (STRAPPA 2015) the serial structures by re-using the substrate rooms around the court space
The process that leads to the construction of new organisms built on a previously existing substratum, varying in the different historical phases, has very different features from that which originate from the transformation of nature: here, matter is, in some way, pre-formed, it already has a shape, placed as it is at the end of an entire life cycle and at the beginning of another. The recognition of this form, linked to the historical and civic environment that created it, is the origin of a new design and constitutes its critical substance. That is why the phases we can identify in this transformation are dialectic: they should be interpreted as far as the interaction between the intentions of the ‘subject’ and the potential of the ‘object’ : they are not strictly chronological.
We can suppose an initial phase of invention, of the invenio involving the random, unplanned relationship with the object being renovated or rediscovered. This occurs when the last phase of a substratum organism’s consumption has ended, sometimes in the distant past, becoming the matter whose characters and attitude to receiving a new form are recognised by the new architect/builder. This first, logical phase therefore concerns the transformation of ‘encountered’ matter. Even before this matter is actually used, it has, at least in part, to do with the builder’s awareness in recognising the substance of which the old spoil is made and therefore to being transformed from matter into material (STRAPPA 1995). Therefore the medieval builder who constructed on ancient ruins and from ancient ruins viewed it as materia signata: the substance of which the substratum city is built and that, despite having lost its significance, is transformed into meaningful heritage. This action is not only a cancellation, but a continuation too, an acknowledgement marked by an identification, followed or not by the passage from the simple use of “found” materials to their transformation. While the term ‘material’ still indicates matter’s suitability to be used in a new building, either in its original form or in a new form, this definition also fits the work of the calcarari (lime kilns workers) that recognised the suitability for construction in the second nature of imperial deposits, cancelling a significant part of our built heritage for centuries. In keeping with the masonry-plastic characters of Roman and Romanised cultural areas, the elements that were produced, apart from linear ones of Greek origin, typically featured two dimensions that prevailed over a third (flat or curved elements) and easily remained continuous, omogeneus and organic with the other elements of a structure. As well as, on the fabric scale, the serial persistence of the base fabric and the singularity of the special organisms continues in other forms. The acknowledgment of the characters and of the building susceptibility of what the ancients have physically left to the new city, therefore, takes place at all scales. It is a metabolization process through which the city consumes the Ancient, regenerating itself, proof of the resilience of the plastic city of which Rome was the greatest expression.
The second phase involves the selection/specialisation, the decision of what role the substrate material (no longer merely matter) will play in a new structure. The selection phase, mainly based on economic and technical considerations, therefore coincides with a acknowledgment of the element ‘encountered’ in the ancient fabric, as an ‘eloquent legacy’, used with a new meaning in a new context. It is a phase that already had significant precedents in Roman times. From a constructive point of view, the choice of elements that could be obtained at different levels mainly involved:
- the size (from the large blocks taken from the remnants of special public buildings to the decorative features reused with a new tectonic purpose);
- the mechanical qualities, particularly their hardness: soft rock like sandstone, chalk, volcanic tuff, or hard rock like marble and granite; next their duration, their ability to stand over time, a feature that gained new symbolic importance in Christian Rome;
- the workability, a feature often opposite but complementary to that of hardness and duration.
However, it also concerns the new typological effort spent in reusing ancient substrate layouts, with the widespread dequantification of special structures and their return to base types functions.Take, as example, the return to base fabric of the Pompeus Theatre (in this issue we are presenting the important study that one of our PhD students, Cristian Sammarco, is conducting on this subject, with the reconstruction of the base building organism originated by the ancient layout’s consumption, through the drawing of the cadastral maps mosaic).
The third, ethical phase, election/designation, concerns the action, the behaviour (ἦθος) contributed by a critical consciousness of the act of reassembilg with which the builder completely considers the problem of the construction element’s meaning within developing urban and architectural structures. As well as through re-employment, the recognition of the ancient structures of elements is evident through the recovery of typical building systems.
There is no doubt that the reassembly of fragments of spolia involves an element of organicity (features such as proportion and congruence) borrowed through the custom with pre-existences. This consideration is even more obvious at the scale of the aggregative organism, of fabric where the continued existence of ancient buildings and urban structures indicates organic and typical proportions (take insulae for example). As mentioned earlier, this way of transforming existing urban lanscape has significant precedents as far back as Ancient Roman times. The reconstruction of the Porticus Octaviae commissioned by Emperor Severus Alexander in 203 A.D. involved the reuse of elements from the earlier Augustan construction. When chosen and rearranged within a new structures, however, they established a new relationship of necessity between elements. This is an early, real ‘nomination’ and ‘designation’ operation, as was to occur extensively after the fall of the Roman Empire. This act of renaming things– which was widely practiced during the fifth century by Theoderic as a political act of reconciliation with the Roman civilitas and saw its first conclusion during the early XIII century– imbued each element with a role in new organisms that was equally structural, symbolic and political. Proof of this is, for example, Pope Honorius’s reconstruction of the Basilica of San Lorenzo Fuori le Mura, where architraves and columns taken from ancient buildings were rearranged in a new structure where, specifically and tellingly, the winged victories of two typical capitals dating from the Antonine era, used to celebrate the victory of Christian martyrs over their persecutors (DE LACHENAL 1995).
The fourth phase involves the symbolic and spatial reorganisation/repositioning of ancient objects, done with a total awareness of the phenomena of building and urban transformation. This corresponds to those great moments of aesthetic distillation, where the substratum also becomes a depository of memory generated by the familiarity with its reuse, clearly demonstrated not only by Baroque revisitations but also by the more pragmatic urban reconstructions of Rome during Umbertino time and even more recently. An obvious example is the construction of Via Nazionale, which took its cue from the city square designed around the great exedra of the Roman baths. But, in general, it is testified by the whole approach to the renovation of the historic city even in restructuring routes that, by their very nature traumatic, were traced with a sensitivity towards substratum constructions that, except for Viale Trastevere, is unequalled in Europe. Take, for example, the case of Corso Rinascimento and the entire renovation programme carried out on the Stadium of Domitian. These interventions, carried out in a climate of widespread fascist rhetoric, would today be considered unacceptable, but nevertheless often capable of reinterpreting types and layouts in a modern way and, at the same time, in keeping with (‘in concordanza di fase’ as Muratori would say) the weight of their history.
10. Ghetto fabric overlapping the remains of the Octavia Portico
In conclusion, I believe that we can surmise a morphological, process-based method of interpreting the substratum that gave rise to modern cities based on cyclical phases of change, analysed, using the tools that architects possess, as meaningful heritage. The effort made to synthetically grasp the processes by turning to morphological methods, which we are by no means suggesting should substitute the essential work of archaeologists and historians, could have a fundamental value for the architectural design by indicating the ways in which not only history has generated new forms, but also how the present, so to speak, flows in the past. This powerful legacy of guidelines – absolutely not oriented towards imitating the past–could support, if we are able to recognise them, the work of contemporary architects: a substratum of multiple, shared meanings, in contrast to the individualistic trend of architectural design. A legacy stratified over time, to be deciphered and interpreted with new eyes identifying within it a new and fertile organicity, as in every phase of the great civil crisis.
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