A “keep” is a fortified tower that was built within a castle during the Middle Ages. This one, which is part of the Óbidos Castle, was constructed in the late 14th century by Portugal’s King Ferdinand I who was also called “The Handsome.” He was the last to reign from the Portuguese House of Bugundy which led to the 1383-1385 Crisis until John I won the Battle of Aljubarrota and began the House of Aviz dynasty.