Iemasa was a retainer of [[Tokugawa Ieyasu]]. He was considered a man of ability and assisted his lord in various military and domestic matters. Notably, he was important in the creation of a Tokugawa-[[Uesugi clan|Uesugi]] alliance in the early 1570's. | Iemasa was a retainer of [[Tokugawa Ieyasu]]. He was considered a man of ability and assisted his lord in various military and domestic matters. Notably, he was important in the creation of a Tokugawa-[[Uesugi clan|Uesugi]] alliance in the early 1570's. |