Around that time, many men took tonsure to be Buddhist monks in order to avoid taxation and labor. In 714, Yao, pointing out that veneration of Buddhist monks did nothing to save Later Zhao, Later Qin, Northern Qi, and Liang Dynasty, suggested that Emperor Xuanzong order a thorough review of the ranks of Buddhist monks and nuns and force those who were not truly devout to return to civilian life and be subject to taxation and labors. Some 12,000, as a result, were forced to return to civilian life. Meanwhile, however, when Yao spoke against a campaign that the general and fellow chancellor Xue Na advocated against the Khitan, Emperor Xuanzong did not listen to him and had Xue attack Khitan anyway. (Xue's campaign eventually ended in failure in fall 714.) Yao and his fellow chancellor Lu Huaishen, meanwhile, also did much to try to eliminate the culture of the nobles exerting influence in civil service matters.