The wealth generated by maritime trade spurred the rise of organized kingdoms on the island, some of which had grown quite powerful by the 17th century. Among these were the Betsimisaraka alliance of the eastern coast and the Sakalava chiefdoms of Menabe and Boina on the west coast. The Kingdom of Imerina, located in the central highlands with its capital at the royal palace of Antananarivo, emerged at around the same time under the leadership of King Andriamanelo.