Porta Praetoria, Roman city gate in Aosta, Italy.

Porta Praetoria is a Roman city gate in Aosta, in the Aosta Valley in northern Italy, built with three openings: a wide central passage for wheeled vehicles and two narrower side passages for people on foot. It consists of two arched sections placed one behind the other, forming a short enclosed passageway between them.

The gate was built around 25 BCE as part of the founding of Augusta Praetoria, the Roman city that became modern Aosta, and served as the main eastern entrance to the settlement. In the medieval period it was absorbed into surrounding buildings, which partly explains why some sections were protected from decay.

Between the outer and inner gate, there is a small covered space that once served as a control zone for travelers, and it is still easy to make out today. Walking through it, visitors can see up close how layers from different periods were added one on top of another.

The gate is located in the center of Aosta and is easy to reach on foot from the main street that runs through the old town. The outer structure can be seen at any time of day, and the passageway is generally open, allowing visitors to walk through and view both archways from inside.

The gate is built of stone blocks bound with crushed slate taken from the bed of the Dora Baltea, which was rich in this material in Roman times. Dark marks on the stone still show where a bread oven stood beneath a chapel built over the eastern central arch in the Middle Ages, mentioned from the 12th century.