As Kamehameha fought to control all the islands, he won a decisive battle at 'Iao Valley, Maui. Landing his war fleet at Kahului while Maui's chief Kahekili was on O'ahu, Kamehameha pursued Kahekili's son Kalanikupule and other Maui chiefs deep into 'Iao Valley. Kamehameha's warriors were aided by his Western cannon, called Lopaka, and his two foreign advisors, John Young and Isaac Davis, who operated it. Many died in the bloody battle called Kepaniwai ("the damming of the waters"), but none of Maui's major chiefs were killed. Many, including chiefess Kalola and her granddaughter Keopuolani, escaped through the mountains to Olowalu and Lahaina. After Kamehameha's victory, Kalola accepted Kamehameha's protection and promised Keopuolani to him as a future wife (she was 11 years old at the time). Despite the defeat of his forces, Kahekili refused to relinquish control of the island; Kamehameha returned later to reconquer the island in 1794.