Ostia (Rome) in the context of "Third Macedonian War"

The Tiber (/ˈtaɪbər/ TY-bər; Italian: Tevere [ˈteːvere]; Latin: Tiberis) is the third-longest river in Italy and the longest in Central Italy, rising in the Apennine Mountains in Emilia-Romagna and flowing 406 km (252 mi) through Tuscany, Umbria, and Lazio, where it is joined by the River Aniene, to the Tyrrhenian Sea, between Ostia and Fiumicino. It drains a basin estimated at 17,375 km (6,709 sq mi). The river has achieved lasting fame as the main watercourse of the city of Rome, which was founded on its eastern banks.

The river rises at Mount Fumaiolo in Central Italy and flows in a generally southerly direction past Perugia and Rome to meet the sea at Ostia. The Tiber has advanced significantly at its mouth, by about 3 km (2 mi), since Roman times, leaving the ancient port of Ostia Antica 6 kilometres (4 miles) inland. However, it does not form a proportional delta, owing to a strong north-flowing sea current close to the shore, due to the steep shelving of the coast, and to slow tectonic subsidence.

Ostia Antica (lit. 'Ancient Ostia') is an ancient Roman city and the port of Rome located at the mouth of the Tiber. It is near modern Ostia, 25 km (16 mi) southwest of Rome. Due to silting and the invasion of sand, the site now lies 3 km (2 mi) from the sea. The name Ostia (the plural of ostium) derives from Latin os 'mouth'.

Ostia is now a large archaeological site noted for the excellent preservation of its ancient buildings, magnificent frescoes and impressive mosaics. The city's decline after antiquity led to harbor deterioration, marshy conditions, and reduced population. Sand dunes covering the site aided its preservation. Its remains provide insights into a city of commercial importance. As in Pompeii, Ostia's ruins provide details about Roman urbanism that are not accessible within the city of Rome itself.

The Basilica of Santa Aurea is a church situated in the Ostia Antica district of Ostia, Italy. Ostia became an episcopal see as early as the 3rd century AD. The present-day church, completed in 1483, is the cathedral of the suburbicarian diocese of Ostia.