What title did Richard of York hold as head of government during Henry VI's illness?

Richard of York held the title Lord Protector while Henry VI was incapacitated by serious mental illness. York was appointed Protector of the Realm in 1453, when Henry’s breakdown left the government unable to function normally.

Henry became unresponsive in August 1453, apparently after England’s defeat at Castillon in the final phase of the Hundred Years’ War. He was unable to speak or recognise people, so the political nation needed a figure to exercise royal authority in his name.

York’s protectorship gave him control over government and strengthened his position against rival courtiers, especially Edmund Beaufort, Duke of Somerset. It did not make York king: his authority formally derived from Henry’s incapacity and was subject to the political structures of the realm.

When Henry recovered in January 1455 after roughly seventeen months, York lost the protectorship and Somerset returned to favour. The reversal intensified the factional conflict that soon produced the First Battle of St Albans and the Wars of the Roses.