- Richest of the Rich position: 2
- Birth/Death: died 1088
- Origin of wealth: Land
- Wealth: £10,000
- Net National Income: £150,000
- Net National Income Percent: 6.66%
- In Today’s Money: £73.923 billion
Conspicuous loyalty to William the Conqueror made William of Warenne one of the richest men in one of the richest kingdoms in Europe. The younger son of Rudolf of Varenne in Normandy, Warenne entered ducal service under the then William of Normandy in the early 1050s as a very young man. He distinguished himself at the Battle of Mortemer in 1054, and was granted estates in upper Normandy, but it was the invasion of England in 1066 that set him on the path to huge wealth. He fought at the Battle of Hastings and was rewarded with lands which within twenty years extended into thirteen counties, most notably strategically important estates in Sussex centred around Lewes.
Through the early period of the Norman conquest, he showed his support for the Crown by playing a leading role in suppressing a revolt by the Earls of Hereford and Norfolk. Life became more difficult after William the Conqueror died and Warenne supported William Rufus in his claim to the throne against Robert Curthouse and Odo of Bayeux. Warenne was rewarded with the title Earl of Surrey in 1088, but did not live long to enjoy it. He was seriously wounded that same year in the Siege of Pevensey by an arrow in his leg and died at Lewes Priory, which he had founded.