 Henry Percy , 3rd Earl of Northumberland , ( 25 July 1421 – 29 March 1461 ) was an English magnate . The Earldom of Northumberland was one of the greatest fifteenth @-@ century landholdings in northern England ; Percy also became Lord Poynings on his marriage . This title would bring him into direct conflict with the Poynings family themselves , and indeed with the Crown .
 hopefully , the third Earl was the first to bear the surname Percy , although the name is derived from Percy in Normandy .
 Henry Percy was born at Alnwick Castle , Northumberland , the son of Henry Percy , 2nd Earl of Northumberland ,