The possibility of a temporary presence of the Tiber outlet in the area of the future imperial harbours (figure, 1st phase), before its migration to the present course alongside Ostia, is now generally accepted, and has found confirmation in several stratigraphic drilling data.
The existence of the settlement is likely, because Livius mentions Ostia twice in his accounts of the fifth century.
Livy mentions floods of the Tiber in 414 and 363 BC (AUC 4.49.2-3 and 7.3.2).
Three recent articles (2010-2011) form a breakthrough in the knowledge of the Holocene history of the coastal area of Rome .
Data were mainly collected from drillings, which were then interpreted from the sedimentological and paleobotanical viewpoint.
The ancient Roman city of Ostia was in antiquity situated at the mouth of the river Tiber, some 30 kilometres to the west of Rome.