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 Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.