William Marshal, 1st Earl of Pembroke

Knighted in 1166, William Marshal made his name and fortune on the tournament circuit, a landless younger son whose family held the hereditary office of Marshal to the King. In 1189 he married Isabel de Clare - daughter of Richard de Clare and Aoife MacMurrough - and became Earl of Pembroke, though the title wasn't officially granted until 1199. He served Henry II, the Young Henry, Richard I, and John as soldier and adviser, his prowess earning him Stephen Langton's tribute as the greatest knight who ever lived. When John died in 1216, the realm appointed seventy-year-old William protector for nine-year-old Henry III and rector regis et regni - governor of king and kingdom. Just before his death on 14 May 1219, he took vows as a Knight Templar, fulfilling a promise he said he'd made in youth while on crusade, and was buried in the Temple Church in London.