Enclos Saint-Césaire, Medieval Benedictine nunnery in Arles, France

Enclos Saint-Césaire is a former medieval Benedictine convent in Arles that originally consisted of walled buildings, a church, and a cloister arranged around a central courtyard. Today the visible remains include thick stone walls and rounded arcades built in the early medieval style typical of southern France.

Founded on 26 August 512 by Archbishop Caesarius of Arles, who installed his sister Caesaria as first abbess, the monastery was first called Saint-Jean. It was suppressed during the French Revolution, sold as national property in 1792 and largely demolished; the remaining buildings later served as a hospice and are now abandoned.

The abbey's name changed from Saint-Jean to Saint-Césaire in honour of Caesaria, the first abbess and sister of the founder. Around 568–569 Radegund, former wife of King Chlothar I, stayed here under abbess Liliole, and the Rule of Caesarius then spread to the monastery she founded at Poitiers. The Vie de Rusticule records churches inside the convent, including one dedicated to the Holy Cross and later to the Archangel Michael.

The abbey stood in the south-eastern corner of Arles' Roman rampart, and the buildings that survived the Revolution were later used as a hospice; they now stand abandoned, so there is no visitor circuit or opening times. The gateway with its single round-headed arch, carved capitals and cornice of projecting blocks can be seen from the street; a small red cross is painted on the stained lower left pier.

The Rule of St Caesarius spread through the Frankish kingdom from this house: Radegund, former wife of King Chlothar I, stayed at Arles around 568–569 under Abbess Liliole, the third abbess, and carried the rule to her foundation at Poitiers. Liliole died shortly after, and on 12 August 632 Archbishop Theodosius attended the funeral of the fourth abbess, later venerated as a saint.