PORTA TIBURTINA
a gate in the Aurelian wall (III. 44), by which the VIA TIBURTINA (q.v.) left the city (DMH). In the eighth century it was known as Porta S. Laurentii, because it led to the church of that name (GMU 88; R ii. 406). There seems to be no trace in the present gate of any work by Aurelian, who may have simply restricted himself to flanking with two towers the arch by which the aquae Marcia, Tepula and Iulia crossed the road. This was rebuilt by Augustus in 5 B.C., and also bears inscriptions of Vespasian and Septimius Severus, relating to the aqueducts (CIL vi. 1244-1246). From the bull's head on the keystone of the arch came the name porta Taurina, which we find in the Liber Pontificalis in the lives of Alexander I (LPD i. 127) and Anastasius I (ib. 258) as well as in the Mirabilia (Jord. ii. 319-328); while Magister Gregorius (JRS 1919, 20, 46) gives both porta Tiburtina and porta Aquileia, que nunc Sancti Laurentii dicitur, in his list.The gate was restored by Honorius, as the inscription over the stone outer arch records (CIL vi. 1190).1 He also built the inner arch 2 in stone, most of which was removed by Pius IX in 1869, and, according to Lanciani, raised the level, here and elsewhere, from 9 to 13 feet; but the difference between the levels of the Augustan and Flavian periods has now been more accurately determined as 1.38 metre (41 feet), while there was a rise of only 1 cm. up to the time of Honorius (Jord. i. I. 356-358; LR 76-77; PBS iii. 85-88; T viii. 9-14; BC 1892, 111; 1917, 207-214).