Conclusions
The analysis of literary sources and historical iconographic documentation, combined with geological data and archaeological records, sheds new light on a few crucial questions about the ancient topography and makes it possible to formulate new hypothesis about the evolution of the ancient military and commercial functional areas of the harbour system of Catania. Taking into account the tectonic uplift (about 2 mm/yr), the area of Piazza Duomo, the most depressed of the city at the mouth of the Amenano river, in the Greek colonization period was located a few meters below the sea-level. This area was successively transformed and levelled, so the present road surface do not allow to appreciate the functional level of use (documented in the archaeological stratigraphy). However, we infer that it was the probable site of a natural inner harbour that was properly perceived at the mouth of the Amenano river as a landing place for the first colonies who founded Catania in the 8th century B.C., and later on as sheltered transit area for maritime exchange during all the Greek Age. The shoreline of the inner port was also protected eastward by a natural landward barrier made of sand. The archaeological evidence arising from the Acropolis, located on Monte Vergine Hill, with the sacred area also arranged with a proper altar (area Purità) since the Arcaic age, and from the supposed Sanctuary of Piazza San Francesco, in the down-town area, clearly suggest intense long-routes relationships. In the area of Ursino Castle, that is located on the top of a 15 m high natural terrace at that time straight facing the sea, a possible strong-hold place was built for the purpose of controlling the harbour movements. According to the literary sources, beside the small river port used for commercial purpose, during the Greek and Hellenistic period the large Plaia beach located immediately south of the town, at present covered by the 1669 lava flow, was used for military purpose. Thucidides (III, 116) mentions Catania during the struggle between Athens and Sparta, as do Diodorus of Sicily (XIV, 59,3; 61,4) writing about the second Punic war: the literary sources here analysed seem to suggest that during the two mentioned wars, the military base for the fleet allied with Catania were positioned on the external southern sandy flat coastline.
During the Roman period, the harbour-town of Catania, first as civitas decumana and from 21 B.C. as a colony, had to face environmental changes related to alluvial episodes and infilling process of the natural harbour by coastal-fluvial deposition. As in the inner port-town of Ostia at the mouth of the Tiber River, a similar process led to the final abandonment of the harbour area, where the Platea Magna was built. In fact, from the early Roman Age onwards, the marshy area was probably reclaimed using special drainage techniques, by which part of the fresh waters were underground canalised and used to supply at least two thermal buildings located down-town (Terme Achilleane, Terme dell’Indirizzo).
Later on, many attempts were done to built a larger and multifunctional harbour, as shown by ancient cartography here considered. To face such unfavourable situation and its adverse marine conditions, since the Roman period a pier was built on the south-eastern side, probably in the area known as “Porticello”, in order to shelter the port from the force of the prevailing winds and waves. This hypothesis is also testified by a late-Roman epigraphy which kept memory of the restoration of moles and meatus urbis which were probably both gravitating round the Platea Magna area and repeatedly destroyed by marine storms. The outer mole testified by a late-Roman epigraphy was built using the opus pilarum system in order to shelter a small commercial functional area, while the meatus urbis allowed the canalisation of the water with convenient drainage technique. From the Roman period to the 19th century, the weak outer mole, abutted on the basaltic Larmisi promontory, repeatedly suffered the destruction by marine storms from the east. A conclusive role has been played by the 1669 lava flow that not only covered the beach at the bottom of the Castello Ursino hill, used in the Greek period for military purpose, but also formed a large promontory south of the mouth of the Amenano river, favouring further fluvial-coastal deposition. Finally, the whole area, between the end of the 19th century and the first half of the 20th century has been absorbed in the town-planning changes related to the modern harbour of Catania.