William Marshal, 1st Earl of Pembroke

William Marshal, 1st Earl of Pembroke (1146 or 1147 – 14 May 1219), also called William the Marshal (Norman French: Williame li Mareschal, French: Guillaume le Maréchal), was an Anglo-Norman soldier and statesman during High Medieval England who served five English kings—Henry II and his son and co-ruler Young Henry, Richard I, John, and Henry III—as a royal adviser and agent and as a warrior of outstanding prowess.

Knighted in 1166, William spent his younger years as a successful competitor in military tournaments; 13th century chronicler Stephen Langton eulogises him as the "best knight that ever lived." In 1189, he became earl of Pembroke through his marriage to Isabel de Clare, whose parents were Aoife MacMurrough and Richard de Clare, 2nd Earl of Pembroke. The title of earl was not officially granted until 1199 and is considered to be the second creation of the Pembroke earldom. In 1216 upon the death of King John, William was appointed protector for John's nine-year-old Henry III and rector regis et regni (Latin for "governor of the king and of the kingdom"). Just before his death, William fulfilled a promise he said he made in his youth while on crusade by taking vows as a Knight Templar, and was buried in the Temple Church in London.

Before William, his father's family held a hereditary title of Marshal to the King, which by his father's time had become recognised as a chief or master marshalcy, involving management over other marshals and functionaries. William became known as "the Marshal", although by his time much of the function was delegated to more specialised representatives (as happened with other functions in the king's household). Because he was an earl, and also known as the marshal, the term "earl marshal" was commonly used, and this later became an established hereditary title in the English peerage.