 Complete the following phrase:  In 213, Cao Cao received the title Duke of Wei  and was given the nine bestowments and a fief of ten cities under his domain, known as Wei. That same year, he marched south and attacked Ruxu. Sun Quans general Lü Meng held off the attacks for about a month, and Cao Cao had to pull back in the end. In 215, Cao Cao moved into and took over 