Lou 楼 is not listed in the Song dynasty classic text Hundred Family Surnames.

Some descendants of dukes Donglou and Xilou adopted Lou 楼, the second character in their names, as their surname.

[3] During the Xianbei Northern Wei dynasty, Emperor Xiaowen (reigned 467–499 AD) implemented a drastic policy of sinicization, ordering his own people to adopt Han surnames.

The Gailou 盖楼 and Helou 贺楼 tribes of Xianbei adopted Lou 楼 as their surname.

[4][5] This lineage of Lous rose to prominence during the Song dynasty, and produced a large number of jinshi degree holders, who had the right to hold office in the central government.