On 4 Sept. 1441 Herleton obtained formal confirmation from Henry VI of his tenure for life of the office of clerk to the justiciar of North Wales and the counties of Cheshire and Flint, with responsibility for keeping the rolls, writs, memoranda and bills of the courts, and for supervising officials of the chamber and lower exchequer within the shire hall at Chester. The tower known as ‘Mayshams Toure’ in Chester castle, where the rolls were kept, was assigned to his use. The post had been granted to him by the justiciar, William de la Pole, earl of Suffolk, as a reward for his exemplary service in the earl’s retinue overseas in the wars in France and to the King in England.
It is not known what happened to Herleton after the duke’s death.
