After the accession of King Henry IV, Cranley undertook a diplomatic mission to Rome, and was made Lord Chancellor of Ireland in 1401.When Henry's son Thomas, Duke of Clarence, was made Lord Deputy of Ireland, Cranley was appointed to his council.[7] The pressure of official business, combined with the effects of ill health and old age, made Cranley increasingly unfit to perform his duties, and in his later years the functions of the Chancellor were usually carried out by his deputies, first Thomas de Everdon, then Laurence Merbury, and then Roger Hawkenshaw.He also became Justiciar of Ireland, following the sudden death of Sir John Stanley in January 1414, although in view of his age and ill health it was understood that this was only a temporary appointment.Despite their expertise, in 1414 the Anglo-Irish suffered one of their worst military defeats of the era, when they were crushed by O'Connor Fahy and his army in County Offaly.