Before the banquet at Hongmen, Xiang Yu planned to attack his rival Liu Bang. Xiang Bo, Xiang Yu’s uncle, “had long been on good terms” with Zhang Liang, who was serving Liu Bang. Xiang Bo “rode by night to Liu Bang’s camp, privately saw Zhang Liang and told him everything.” He urged his friend to come away with him and not die along with Liu Bang. (Records of the Grand Historian)
Zhang Liang took the news to Liu Bang. When Liu Bang asked how he knew Xiang Bo, Zhang Liang explained: “In the Qin days he was my companion. Xiang Bo killed a man, and I saved his life.”