This is recorded in Dutch history as "Het verraad van Teukoe Oemar" (The Treason of Teuku Umar). From the mid-1880s, the Acehnese military leadership was dominated by religious ulema, including Teungku Chik di Tiro (Muhamma Saman), who propagated the concept of a "holy war" through sermons and texts known as "hikayat" or poetic tales. Acehnese fighters viewed themselves as religious martyrs fighting "infidel invaders". By this stage, the Aceh War was being used as a symbol of Muslim resistance to Western imperialism. In 1892 and 1893 Aceh remained independent, despite the Dutch efforts. Major J. B. van Heutsz, a colonial military leader, then wrote a series of articles on Aceh. He was supported by Dr. Christiaan Snouck Hurgronje of the University of Leiden, then the leading Dutch expert on Islam. Hurgronje managed to get the confidence of many Aceh leaders and gathered valuable intelligence for the Dutch government on the activities of Indonesian Hajj pilgrims. His works remained an official secret for many years. In Hurgronje's analysis of Acehnese society, he minimised the role of the Sultan and argued that attention should be paid to the hereditary chiefs and nobles, the "Ulee Balang", who he felt could be trusted as local administrators. However, he argued, Aceh's religious leaders, the "ulema", could not be trusted or persuaded to co-operate, and must be destroyed. As part of a policy of divide-and-conquer, Hurgronje urged the Dutch leadership to widen the existing gulf between the Acehnese nobility and the religious leaders. Hurgronje was a friend of the Arab Grand Mufti of Batavia, Habib Usman bin Yahya, who issued a fatwa to support the Dutch war against Aceh. In 1894, the "penghulu" or judge Hasan Mustafa also helped bring a stop to the fighting by issuing a fatwa, telling the Muslims to submit to the Dutch colonial government. In 1898 Van Heutsz was proclaimed governor of Aceh, and with his lieutenant, later Dutch Prime Minister Hendrikus Colijn, would finally conquer most of Aceh. They followed Hurgronje's suggestions, finding cooperative "uleebelang" that would support them in the countryside and isolating the resistance from their rural support base.