북연
In fall 432, Northern Wei's Emperor Taiwu made the first major attack of Feng Hong's reign, heading for Northern Yan's capital Helong (和龍, in modern Jinzhou, Liaoning). Feng Hong tried to appease the Northern Wei emperor by delivering gifts of beef and wine to his army, to no avail. 10 Northern Yan commanderies surrendered to Northern Wei, and Northern Wei forces captured a number of Northern Yan cities and put Helong under siege. However, two months later, Emperor Taiwu withdrew after capturing 30,000 households from Northern Yan and relocating them to his You Province (幽州, modern Beijing, Tianjin, and northern Hebei). Feng Hong's official Guo Yuan (郭淵) suggested to Feng Hong that he offer to be a Northern Wei vassal and send a daughter to be Emperor Taiwu's consort, but Feng Hong refused, stating that the enmity between the states were so deep that he would be killed anyway even if he surrendered. (While Northern Wei was sieging Helong, the Northern Wei general Zhu Xiuzhi (朱脩之), who had been captured from Liu Song, plotted to assassinate Emperor Taiwu and then join Feng Hong, but his plot was discovered, and he fled to Feng Hong, who in turn sent him back to Liu Song, seeking Liu Song aid. Henceforth, Liu Song and Northern Yan were informal allies, although Liu Song provided little actual help.)