Porte d'Arroux, Roman gate monument in Autun, France

The Porte d'Arroux is a two-storey Roman gate of large pale grey and tan blocks, weathered with dark streaks. Two wide round-headed arches for vehicles stand side by side, each framed by a projecting archivolt, with a smaller archway to the far right for pedestrians; above a horizontal band runs a gallery of seven round-headed openings between columns, open to the sky and crowned by a flat stone top. It spans a paved road in Autun.

Built under Augustus together with the 6 km wall of Augustodunum, the gate controlled the road north toward Auxerre and was probably finished at the start or end of his reign. In the Middle Ages it became the chapel of Notre-Dame d'Arroux, losing its flanking towers, the inner courtyard building and most of the upper gallery. It was classified as a monument historique in 1846.

In the Middle Ages the gate was converted into the Chapel of Notre-Dame d'Arroux, which explains why the flanking towers and the inner courtyard building vanished. The name Arroux comes from the river crossed just outside the gate on the road north to Auxerre. Look for the grooves cut into the stone for the portcullis that closed the central passages.

The monument is freely accessible year-round without entrance fees and can be visited at any time. The best views come from street level, as the interior is not open to visitors and the exterior structure reveals all the architectural details worth seeing.

The gate's two monumental flanking towers, each about 10 metres wide, have vanished, but a 19th-century plan by Jean Roidot-Déléage still shows part of one of them. The gate also became a chapel, Notre-Dame d'Arroux, probably in the Middle Ages.