Born in 1563, Kato Yoshiaki served Toyotomi Hideyoshi from a young age. At the Battle of Shizugatake in 1583 he distinguished himself in combat and was counted among the "Seven Spears of Shizugatake" alongside Fukushima Masanori and Kato Kiyomasa. He later became lord of Masaki Castle in Iyo Province and led naval forces in the Korean campaigns. At the Battle of Sekigahara in 1600 he fought for the Eastern army and was rewarded with an expanded domain in Iyo. In 1601 he obtained Tokugawa Ieyasu's permission to build a new castle on Mount Katsuyama, beginning construction the following year. In 1603 he moved his base from Masaki to Katsuyama and renamed the area "Matsuyama." The project proved a massive undertaking that would take over a quarter century; before its completion, in 1627, following the extinction of the Gamo line at Aizu, Yoshiaki was transferred there. Completion of Matsuyama Castle was left to his successors, the Gamo and later Matsudaira clans. He died in 1631 at age 69. Both Matsuyama Castle and the city's very name trace their origin to Yoshiaki's founding vision.