It was located next to Porta San Giovanni and was originally a small gate without towers that allowed passing through the Aurelian Walls to reach Via Asinara, and further on Via Tuscolana. 

The name seems to come from the Asinii family that owned properties in the surroundings or perhaps is due to the fact that many donkeys (asini) passed through it carrying goods. In the fifth century the gate was completely rebuilt by Emperor Honorius (395-423 A.D.), when the entrance arch covered with travertine was made wider and two semicircular towers were added on the sides. 

A storm door and a safety courtyard were built internally. The Byzantine General Belisarius entered Rome through this door in 536 A.D., while the Goths fled through Porta Flaminia, and ten years later the king of the Ostrogoths Totila. 

The gate was kept open until the time of Pope Pious the Forth (1559-1565) and was then definitively closed and replaced by Porta San Giovanni, built by Pope Gregory the Thirteenth in 1573. In 1951 the Municipality of Rome restored the monument back to its original appearance after years of complete underground burial.