William de Percy (c 1030-1096) came to England with William the Conqueror, and Richard Percy (c 1170-1244) was one of the barons who extorted Magna Carta. Henry Percy (c 1272-1315) assisted Edward I against the Scots, and in 1309, he purchased the barony of Alnwick from Bishop Bek of Durham; from that time, Alnwick became the chief seat of the family. It is the largest inhabited fortress in the country after Windsor Castle.
Before the Percys, Alnwick had seen the death of the Scottish king, Malcolm III (Canmore), in 1093 during his fifth invasion of England. This is Shakespeare's Malcolm, who appears in Macbeth. Another Scottish king, William the Lion, was captured there in 1174, and taken to the new keep in Newcastle. The Percy family reigned in Northumberland as virtual kings after 1309, and conducted hostilities along the frontier with Scotland almost as a family affair. Henry's son helped to defeat the Scots in 1346 at Neville's Cross, while his grandson fought at Crecy.

His great grandson, Henry, fourth Lord Percy of Alnwick (1342-1408) was made Marshal of England and 1st Earl of Northumberland. This Henry Percy had a significant role in placing the usurper Bolingbroke on the throne of England as Henry IV. Percy's son, Harry (1364-1403), was known as Hotspur for his reckless courage. In time, Henry Percy came to feel ill- rewarded for his service against the Scots on the northern frontier and for his help in making Henry IV king. Besides this, the Percys distrusted the king's reliance on the hated Neville family (q.v.). Meanwhile, Harry Hotspur had distinguished himself in battle against the French and the Scots (he was a Knight of the Garter at 23). Prince Hal envied him his valour, but by killing him, made his own reputation.
After Hotspur's death on 21 July 1403, at a place north of Shrewsbury, still called Battlefield, Henry IV's army reduced the great Northumberland fortresses without trouble, Warkworth becoming the first English castle to fall to artillery. The gallant Hotspur is commemorated in the gate that bears his name at Alnwick, while the stiff-tailed Percy lion can be seen on Warkworth Castle and on the bridge at Alnwick Castle. It also stands (in lead) on top of Syon House at the Northumberland seat on the Thames in outer London. A facade in Northumberland Street in Newcastle bears the effigies of four men eminent in the region's history. One of them is Harry Hotspur.

Later Earls of Northumberland had a chequered history. The second and third were killed during the Wars of the Roses, and the fourth was murdered. The sixth earl courted Ann Boleyn but was displaced by Henry VIII, who later demonstrated his brutal humour by appointing the earl to the commission which was to try Ann. He feigned illness and died childless in 1537. As his brother had been executed for his part in the northern rising known as the Pilgrimage of Grace, the title was conferred by Edward VI upon John Dudley, Earl of Warwick, who was attainted and executed in 1553 for placing Lady Jane Grey on the English throne. The seventh Earl was beheaded in 1572 for his part in the Rising of the North, and the eighth found dead in the Tower in 1585, where the ninth Earl spent fifteen years as a prisoner, for his supposed connection with the Gunpowder Plot. The tenth Earl fought against Charles I in the Civil War and then helped in the restoration of the monarchy.
From the times of Hotspur and his successors in the Earldom, 'The Magnificent', 'The Unthrifty', 'The Wizard', whether upholding the crown or opposing it, the death of Northumberland was always a national event.

The Percys owned property at Tottenham in London and the name Hotspur was adopted first by the local cricket club and in 1882 by the Hotspur football club. This later became the famous Tottenham Hotspur FC.