Castres grew up round the Benedictine abbey of Saint Benoît. Castres became an important stop on the international pilgrimage routes to Santiago de Compostela in Spain because its abbey-church, built in the 9th century, was keeping the relics of Saint Vincent, the renowned martyr of Spain. It was a place of some importance as early as the 12th century, and ranked as the second town of the Albigeois behind Albi.