Sun Quan was well aware of Cao Cao's intentions, and he quickly entered into an alliance with Liu Bei and Liu Qi to prepare for an attack by Cao. Cao Cao wrote Sun Quan with a letter intending to intimidate, and in face of Cao's overwhelming force (estimated to be about 220,000 men, although Cao claimed 800,000, against Sun's 30,000 and the Lius' combined force of 10,000), many of Sun's subordinates, including Zhang Zhao, advocated surrender. Sun Quan refused, under advice from Zhou Yu and Lu Su that Cao Cao would surely not tolerate him even if he surrendered.
