The 17th head, Yoshihiro (1535–1619), was the "daimyō" at the time of the Battle of Sekigahara, the establishment of the Tokugawa Shogunate, and the Siege of Osaka. His nephew and successor was Tadatsune. He held significant power during the first two decades of the 17th century, and organized the Shimazu invasion of the Ryūkyū Kingdom (modern-day Okinawa Prefecture) in 1609. The "Shōgun" allowed this because he wished to appease the Shimazu and prevent potential uprisings after their loss at Sekigahara. The trade benefits thus acquired, and the political prestige of being the only "daimyō" family to control an entire foreign country secured the Shimazu's position as one of the most powerful "daimyō" families in Japan at the time.