Cly was first mentioned in a document from 1207, in which the "chapel sancti Mauricij (Saint Maurice) de castro Cliuo" is mentioned among the goods of the Vicarage of Saint-Gilles in Verrès,[2] but the keep has been dated to 1027 using an analysis of the tree rings in its timbers (dendrochronology). Originally a fief held from the Counts of Savoy, in 1376 the direct ownership passed to the Duchy of Savoy, which installed a castellan to administer it for them until abandoned in 1550.