In an attempt to protect his eastern borders, Oda Nobuhide built Iwasaki Castle in the early 16th century. The castle changed hands in 1529, when Matsudaira Kiyoyasu seized it and made the castle headquarters for the Matsudaira clan. Kiyoyasu's son, Matsudaira Hirotada, moved his residence elsewhere after Kiyoyasu was assassinated in 1535 by one of his retainers, Abe Masatoyo. Niwa Ujikiyo was placed in control of the castle and his descendents continued to rule out of it until Battle of Iwasaki Castle in 1584. The Battle of Iwasaki was part of the larger Battle of Komaki and Nagakute, and during the battle the castle was besieged and taken by the Toyotomi clan's forces led by Ikeda Tsuneoki. The garrison, led by Niwa Ujitsugu, suffered numerous casualties including 300 killed, Ujitsugu's