A former palace of King Charles I of Spain (1500 – 1558), this convent was founded by Joanna of Austria (1535 – 1573), his daughter, in 1557. Once a wealthy convent, it boasts a remarkable collection of art and relics today, including marble sculptures, supposed pieces of Christ's cross and the bones of Saint Sebastian. These items were kept intact inside the convent after the Franciscan Sisters took a vow of poverty and forbade auctioning of the precious relics. It was only converted into a museum after the Pope intervened upon seeing the living conditions of the Sisters. Today, despite being a museum, the convent still houses several Franciscan nuns, who live in solidarity in an enclosed area. The convent is particularly popular during Holy Week, where processions take place within the cloister.