Rolande de Colline
Sir Rolande de Colline was apparently Ankh-Morpork's very first Postmaster General, some four hundred years before the present. He has so far only featured in the Post Office yearly diary.
Annotation
Sir Rolande's name suggests Sir Rowland Hill ("colline" being French or Quirmian for "hill"), who was merely the Secretary to the UK Postmaster General, but was nonetheless responsible for much the same reforms in the British Royal Mail as Moist von Lipwig would oversee at the Ankh-Morpork Post Office, including the postage stamp.