Claim: The House of Percy, known to be one of the most powerful noble families in Northern England for much of the Middle Ages, known for their long rivalry with another powerful northern English family, the House of Neville, was founded in 1067 by William de Percy, 1st feudal baron of Topcliffe in the Kingdom of England, United Kingdom.
Evidence: They were one of the most powerful noble families in Northern England for much of the Middle Ages, known for their long rivalry with another powerful northern English family, the House of Neville. 1067 William de Percy (d.1096), 1st feudal baron of Topcliffe Kingdom of England, United Kingdom