Emperor Kangxi (reigned 1662-1722) of the Qing dynasty was one of the most admired rulers in Chinese history. Kangxi became emperor when he was only seven. The government was at first in the hands of regents, but when he was sixteen, Kangxi boldly took power for himself. The Qing rulers had conquered China only 25 years previously. They were Manchus, northerners from beyond the Great Wall. Only four years after Kangxi took control, there was a massive rebellion which could have broken the dynasty, but under the young emperor's strong leadership, Qing armies crushed the rebels. Kangxi extended Qing control over Taiwan and Tibet, he agreed borders and trade relations with Russia, and he personally led Qing armies against the Zunghar Mongols. Not only an effective military leader, Kangxi was also a highly cultured and sensitive man. He showed great respect for Chinese civilisation, sponsoring arts and cultural projects, and was open also to western learning, interested in math and science. He issued an edict in 1692 tolerating Christianity, although subsequent disagreements between Kangxi and the Pope about whether Chinese Christians could continue ancestor worship led to many missionaries being expelled.