Wou Sankwei did not wait for their coming. Li had sent a strong force to meet him, with instructions either to negotiate or to fight. Wou chose the latter, and delivered battle with such energy and success that more than twenty thousand of the opposing force were laid in death upon the field, no quarter being given to the flying host. News of this perilous reverse roused Li to vigorous action. Knowing nothing of the approach of a Tartar army, he imagined that he had only Wou with whom to deal, and marched against him in person with sixty thousand men, the pick of his victorious army. This large force, perhaps three times the number that the loyal leader could put in the field, reached Wou's station on the river Lanho before the vanguard of the Manchus had appeared. It was obviously Wou's policy to defer the action, but Li gave him no opportunity, making at once an impetuous attack, his line being formed in the shape of a crescent, with the design of overlapping the flanks of the foe. Skilled and experienced as Wou was, the smallness of his force made him unable to avoid this movement of his enemy, who, from a hill where he had taken his station to overlook the battle, had the satisfaction of seeing the opposing army completely surrounded by his numerous battalions. Wou and his men fought with desperate courage, but it was evident that they could not long hold out against such odds. Fortunately for them, at this critical moment a strong Manchu corps reached the field, and at once made a furious charge upon the nearly victorious troops. This diversion caused a complete change in the situation. Li's troops, filled with terror at the vigorous and unexpected assault, broke and fled, pursued by their foes with such bloodthirsty fury that thirty thousand of them were slain. Li escaped with a few hundred horsemen from the disastrous field which was to prove the turning-point in his career. The delayed Manchus soon after appeared in numbers, and Wou lost no time in following up his signal success. Peking was quickly reached, and there, on the eastern ramparts, the victor was greeted with the spectacle of his father's head on the wall, Li having thus wreaked what vengeance he could upon his foe. It was an unwise act of ferocity, since it rendered impossible any future reconciliation with his opponent.