In September 1189 Hamo claimed that he had been appointed to the treasurership in 1181, but did not actually hold the office until 1199. Hamo probably was part of a deputation to Germany by members of the
cathedral chapter when Geoffrey tried to interfere in the election of a dean, against the choice of the chapter. The king,
Richard, was being held prisoner there and in order to secure the royal approval for the chapter's choice, the canons had to send a deputation to the king. They were successful and secured their choice over Geoffrey's. The historian Everett Crosby notes that Hamo was not a witness to any of Geoffrey's surviving charters from the 1190s, although Hamo's own charters are extant. Crosby feels that this is a sign of conflict between Geoffrey and the cathedral chapter at York during this period. By 1199 Hamo was treasurer of York, an office he held along with the Archdeaconry of East Riding, as the two had been combined for over 100 years. Hamo was the final treasurer to hold the East Riding alongside the treasurership, being last-named in the office in 1216. Besides those offices in the cathedral chapter, Hamo received the office of
sacrist of the chapel of St Mary and Holy Angels before 22 November 1181, when he is recorded in that office. In September 1186, Hamo was one of the candidates for the archbishopric of York put forward by the cathedral chapter, but King
Henry II did not approve of his candidature and he did not get elected. In 1208, he had a monetary interest in
Bishop Wilton. When Archbishop Geoffrey died, King
John wrote to the cathedral chapter at York, forbidding them to elect Hamo to the see. If they did so, John told them they would be out of favour, and the chapter seems to have taken this to heart as Hamo was not selected as Geoffrey's successor. ==Death and legacy==