In 717 BC, Duke Zhuang of Zheng went to the capital for an audience with King Huan. During the encounter the duke felt he was not treated with the respect and etiquette which would have been appropriate, given that Zheng was now the chief protector of the capital. In 715 BC Zheng also became involved in a border dispute with Lu regarding the Fields of Xu. The fields had been put in the care of Lu by the king for the exclusive purpose of producing royal sacrifices for the sacred Mount Tai. For Zheng to regard the fields as just any other piece of land was an insult to the court.