The Porta San Paolo is one of the southern gates in the 3rd-century Aurelian Walls of Rome. The Via Ostiense Museum is housed within the gatehouse.
The original name of the gate was Porta Ostiensis, because it was located of the beginning of via Ostiense, the road that connected Rome and Ostia where functioned as its main gate. Via Ostiense was an important arterial road, as evidenced by the fact that upon entering the gate of the same name, the road split, with one direction leading to the famous Emporium, the great market of Rome.
The gatehouse is flanked by two cylindrical towers, and has two entrances, which had been covered by a second, single-opening gate, built in front of the first by the Byzantine general Belisarius (530s–540s).
The structure is due to Maxentius, in the 4th century, but the two towers were heightened by Honorius. Its original — Latin — name was Porta Ostiensis, since it opened on the way to Ostia. Later, it was renamed to the Italian Porta San Paolo, because it was the exit of Rome that led to the Basilica of St. Paul Outside the Walls.
In 549, Rome was under siege; the Ostrogoths of Totila entered through this gate, because of the treason of the Isaurian garrison. On 10 September 1943, two days after the armistice between the Allies and Italy had been agreed, Italian military and civil forces tried to block German seizure of the city, with 570 casualties.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.