The first arch of its time built to honor the achievements of a ruler. In this case it is built to honor Titus though it was built after his death by his brother, Domitian. Specifically, this arch commemorates the military success that was the sack of Jerusalem (see below).
The arch now stands as a tourist attraction and one of the sites to be seen along the Via Sacra. But, it has been restored by the Pope and used as a defensive tower during the Medieval times. Like so many other ancient structures of its time, it has transformed in use and meaning since the years of its creation.