The lordship of the Bishop of Salamanca Historical milestone · San Martín del Castañar, Sierra de Francia, Salamanca Image of San Martín del Castañar, not of the place itself. Alfonso IX of León donated the town in 1225 to the bishop of Salamanca as a private lordship, which kept it outside the county of Miranda del Castañar and explains much of its later development as the ecclesiastical head of the range. 1225 Photo: Nataviajera (CC BY-SA 4.0) What to see and do in San Martín del Castañar