MEDINA SIDONIA, or Medinasidonia, a town of southern Spain, in the province of Cadiz, 21 m. by road E.S.E. of Cadiz. Pop. (1900), 11,040. Medina Sidonia is built on an isolated hill surrounded by a cultivated plain. It contains a fine Gothic church, several convents, and the ancestral palace of the dukes of Medina Sidonia. It has a small agricultural trade, chiefly in wheat, olives and oats.
Medina Sidonia has been identified by some with the Asido of Pliny, but this is uncertain. Under the Visigoths the place was erected into a bishopric (Assidonia), and attained some importance; in the beginning of the 8th century it was taken by Tariq. In the time of Idrisi (12th century) the province of Shadūna or Shidona included, among other towns, Seville and Carmona; later Arab geographers place Shadūna in the province of Seville.