From the Wikipedia page 
John Howard, 1st Duke of Norfolk, KG, Earl Marshal (c.1425 – 22 August 1485) was an English nobleman and soldier, and the first Howard Duke of Norfolk. He was a close friend and loyal supporter of King Richard III, with whom he was slain at the Battle of Bosworth.
He was a staunch adherent of the House of York during the Wars of the Roses, and was knighted by King Edward IV at the Battle of Towton on 29 March 1461, and in the same year was appointed Constable of Norwich and Colchester castles, and became part of the royal household as one of the King's carvers, 'the start of a service to the house of York which was to last for the rest of his life'.
In 1461 Howard was High Sheriff of Norfolk and Suffolk, and during the years 1462-4 he took part in military campaigns against the Lancastrians. In 1467 he served as deputy for Norfolk as Earl Marshal at 'the most splendid tournament of the age when Antoine, count of La Roche, the Bastard of Burgundy, jousted against the Queen's brother, Lord Scales. In the same year he was one of three ambassadors sent to Burgundy to arrange the marriage of the King's sister, Margaret of York, to Charles, Duke of Burgundy. At about this time he was made a member of the King's council, and in 1468 he was among those who escorted Margaret to Burgundy for her wedding.
Howard's advancement in the King's household continued. By 1467 he was a knight of the body, and in September 1468 was appointed Treasurer of the Royal Household, an office which he held for only two years, until Edward lost the throne in 1470.
According to Crawford, Howard was a wealthy man by 1470, when Edward IV's first reign ended and he went into exile on the continent. In the area around Stoke by Nayland Howard held some sixteen manors, seven of which the King had granted him in 1462. After 1463 he purchased a number of others manors, including six forfeited by John de Vere, 12th Earl of Oxford, the son of his cousin, Elizabeth Howard.
Howard was summoned to Parliament from 15 October 1470 by writs directed to Iohanni Howard de Howard Militi and Iohanni Howard Chivaler, whereby he is held to have become Lord Howard. On 24 April 1472 he was admitted to the Order of the Garter.
In April 1483 he bore the royal banner at the funeral of King Edward IV, and was appointed Lord High Steward, and bore the crown before Richard III at his coronation. His eldest son, the Earl of Surrey, carried the Sword of State.
For his support of Richard III during the deposition of King Edward V, he was created Duke of Norfolk, third creation, on 28 June 1483, the first creation of the dukedom of Norfolk having become extinct on the death of John de Mowbray, 4th Duke of Norfolk, in 1476, and the second creation having been invalidated by the illegitimization, on 25 June 1483, of Richard of Shrewsbury, 1st Duke of York, one of the Princes in the Tower, who was also 1st Duke of Norfolk. Norfolk was also created Earl Marshal, and Lord Admiral of all England, Ireland, and Aquitaine.
John Howard was slain at the Battle of Bosworth Field on 22 August 1485 along with his friend and patron King Richard. Howard was the commander of the vanguard, and his son, the Earl of Surrey, his lieutenant. Howard was killed when a Lancastrian arrow struck him in the face after the face guard had been torn off his helmet during an earlier altercation with the Earl of Oxford. He was slain prior to King Richard, which had a demoralising effect on the king. Shakespeare relates how, the night before, someone had left John Howard a note attached to his tent warning him that King Richard III, his "master," was going to be double-crossed (which he was):
“Jack of Norfolk, be not too bold, For Dickon, thy master, is bought and sold.”
However, this story does not appear prior to Edward Hall in 1548, so the story may well be an apocryphal embellishment of a later era. He was buried in Thetford Priory, but his body seems to have been moved at the Reformation, possibly to the tomb of the 3rd Duke of Norfolk at Framlingham Church. The monumental brass of his first wife Katherine Moleyns can, however, still be seen in Suffolk.