The Song dynasty historian Ouyang Xiu traced the Ouyang surname to Ti (蹄, pinyin: Tí), a prince of Yue, the second son of King Wujiang (無疆). After his state was extinguished by the state of Chu, Ti and his family lived in the south side of the Mount Ouyu (歐余山, currently called Mount Sheng 升山 in Huzhou, Zhejiang). In Classical Chinese, the south side of a mountain or the north bank of a river is called Yang (陽), thus the Ti family was called Ouyang. He was called Marquis of Ouyang Village (歐陽亭侯). Traditionally, Ti's ancestry can be traced through his father Wujiang, the King of Yue, to the semi-legendary Yu the Great (大禹). 

https://en.wikipedia.org/wiki/Ouyang

https://en.wikipedia.org/wiki/Ouyang_Xiu