Sanpou also agreed to accept Chinese education, and as his reward Taitsong gave him one of his daughters as a wife. It is stated that one of his first reforms was to abolish the national practice of painting the face, and he also built a walled city to proclaim his glory as the son-in-law of the Emperor of China. During Taitsong's life there was no further trouble on the side of Tibet. Taitsong was not so fortunate in his relations with Corea, where a stubborn people and an inaccessible country imposed a bar to his ambition. Attempts had been made at earlier periods to bring Corea under the influence of the Chinese ruler, and to treat it as a tributary state. A certain measure of success had occasionaly attended these attempts, but on the whole Corea had preserved its independence. When Taitsong in the plenitude of his power called upon the King of Corea to pay tribute, and to return to his subordinate position, he received a defiant reply, and the Coreans began to encroach on Sinlo, a small state which threw itself on the protection of China. The name of Corea at this time was Kaoli, and the supreme direction of affairs at this period was held by a noble named Chuen Gaisoowun, who had murdered his own sovereign. Taitsong, irritated by his defiance, sent a large army to the frontier, and when Gaisoowun, alarmed by the storm he had raised, made a humble submission and sent the proper tribute, the emperor gave expression to his displeasure and disapproval of the regicide's acts by rejecting his gifts and announcing his resolve to prosecute the war. It is never prudent to drive an opponent to desperation, and Gaisoowun, who might have been a good neighbor if Taitsong had accepted his offer, proved a bitter and determined antagonist. The first campaign was marked by the expected success of the Chinese army. The Coreans were defeated in several battles, several important towns were captured, but Taitsong had to admit that these successes were purchased at the heavy loss of twenty-five thousand of his best troops. The second campaign resolved itself into the siege and defense of Anshu, an important town near the Yaloo River. Gaisoowun raised an enormous force with the view of effecting its relief, and he attempted to overwhelm the Chinese by superior numbers. But the better discipline and tactics of the Chinese turned the day, and the Corean army was driven in rout from the field. But this signal success did not entail the surrender of Anshu, which was gallantly defended. The scarcity of supplies and the approach of winter compelled the Chinese emperor to raise the siege after he had remained before the place for several months, and it is stated that as the Chinese broke up their camp the commandant appeared on the walls and wished them "a pleasant journey." After this rebuff Taitsong did not renew his attempt to annex Corea, although to the end of his life he refused to hold any relations with Gaisoowun.