There, Shaykh Ma al Aynin had begun a campaign to counteract the influence of his two rivals—the southern marabouts, Shaykh Sidiya and Shaykh Saad—and to stop the advance of the French. Because Shaykh Ma al Aynin enjoyed military as well as moral support from Morocco, the policy of peaceful pacification gave way to active conquest. In return for support, Shaykh Ma al Aynin recognized the Moroccan sultan's claims to sovereignty over Mauritania, which formed the basis for much of Morocco's claim to Mauritania in the late twentieth century.