The long, stark wall of the Mosteiro de San Paio de Antealtares faces the cathedral's east end across Praza da Quintana. Founded by Alfonso II in the 9th century for Benedictine monks to look after St James' relics, it became a nunnery in 1499.
Up the steps at the top of the plaza, you'll find the entrance to the convent church, above which stands the beatific figure of the 10th-century Galician child saint San Paio, his throat being slashed in reference to his martyrdom in Córdoba. The church gives access to the Museo de Arte Sacra, containing the original altar raised over the Santiago relics. At 8pm (7.30pm on Saturday and Sunday) you can hear the nuns sing vespers in the church.