It is proposed that the fifth stage in the history of the Moro Wars began with the refortification of Zamboanga in 1718 and ended in the Spanish failure in the eighteenth century to reduce the Muslim states to vassalage. To achieve this political end, and Spanish plan was devised to convert the sultans of Sulu and Maguindanao preparatory to the eventual conversion of the datus and other subjects. In this stage, the combined Sulu-Maranao attack to capture Zamboanga in 1719 failed. Again, a desultory war followed. The plan to convert the sultans failed in the case of Maguindanao. Although 'Azim-ud-Din, the sultan deposed by his brother, was baptized in Manila in 1751, that action did not have the desired political results in Sulu since the sultanate was in the hands of a usurper. Also, the question of the sincerity of the conversion still remains an open one.