Battle of Kepaniwai

While Maui's king Kahekili II was on Oʻahu, Kamehameha's war fleet landed in Kahului a few kilometers from the base of ʻĪao Valley. An army consisting of around twelve hundred skilled warriors led by Kamehameha and Kekuhaupiʻo, advanced on Kahekili's son Kalanikūpule and other Maui chiefs blocking the ʻĪao valley. The two armies were evenly matched and neither side broke after two days of fighting. On the third day Kamehameha's army was helped by the use of two cannons (named "Lopaka" and "Kalola") operated by John Young and Isaac Davis, two of Kamehameha's royal advisors. Although none of Maui's major chiefs were killed, many people died resulting in the "damming of the waters" by the corpses floating in the river. It was said that the river "ran red with the blood of the dead." Chiefess Kalola and her granddaughter Keōpūolani were able to escape west through the valley to Olowalu and north to Lahaina.

• http://en.wikipedia.org/wiki/Battle of Kepaniwai