Mogami

The Mogami were a cadet branch of the Shiba, kin of the Ashikaga and of Seiwa Genji blood. Their founder Shiba Kaneyori entered the Mogami district of Dewa in the 1350s, built Yamagata Castle and took the name Mogami; in 1368 he defeated Southern Court forces at Urushikawa.

His successors planted cadet houses across the district, but these grew independent. After the Mogami were defeated by Date Tanemune at Hasedō in 1514, Yoshimori retook Hasedō on reaching adulthood. His daughter Yoshihime married Date Terumune and became the mother of Date Masamune.

Under Yoshimori's son Yoshiaki the house reached its height. He submitted to Toyotomi Hideyoshi in 1590 and held Hasedō Castle against Uesugi Kagekatsu in 1600. After his death in 1614 succession feuds undid the house: it was attainted in 1622, and its descendants became hatamoto in Ōmi.