PORTA LATINA.
(Closed.)
On the keystone is a Greek cross within a circle. The outside of the arch is reached by passing through the Porta S. Sebastiano and turning to the left. It is formed of two round brick towers and a travertine stone arch, with grooves for a portcullis; on the outside keystone are the early Christian emblems of the labarum. The Roman Catholic tradition is that S. John the Evangelist was thrown into a caldron of boiling oil inside this gate, where the circular church now stands.
Opposite is the Church of S. John, Port Latin.
The little round church is called