Castel of Nice Cathedral, Pre-Romanesque cathedral in Cimiez, Nice, France.

The Castel of Nice Cathedral is a ruined pre-Romanesque cathedral on the castle hill of Nice. Only low fragments of stone masonry remain, built from small, irregular grey and beige stones set in mortar, with a raised section on the left featuring a projecting rounded base and scattered rectangular blocks toward the centre and right. None of the walls rises above knee height, and two short square stone pillars or pedestals sit near the middle.

The first cathedral on the castle hill was built at the end of the 10th century in pre-Romanesque style; its high altar was consecrated in 1049. Rebuilt on the same plan in the 13th century and given chapels in the 15th, it was severely damaged in the 1691 siege and demolished in 1706. The bishop's seat had already moved to Sainte-Réparate in 1590.

The name Sainte-Marie recalls the cathedral's dedication to the Virgin Mary, and the see it held was that of Cimiez, a diocese joined to Nice as early as 465. The Duchess of Savoy, Beatrice of Portugal, was buried in the 15th-century church. Visitors today see only low courses of small grey and beige stones set in mortar, with two square pedestals near the middle.

The site is accessible through several pathways that climb the hill through the Cimiez neighborhood. Allow time for the walk uphill and note that routes may become slippery depending on weather conditions.

The cathedral's high altar was consecrated in 1049, and the building had three aisles without a transept and a choir with three apses. The Duchess of Savoy, Beatrice of Portugal, was buried in the 15th-century church before it was demolished in 1706.