From the longer Wikipedia page 
In the 1460s he was appointed Esquire for the body to Elizabeth Woodville, Queen of Edward IV. From 1471 until 1481 he was MP for Wiltshire and in 1479 was appointed Master of the Horse.
He was present when the Treaty of Picquigny was signed in 1475, and remained behind as a hostage of King Louis XI of France until King Edward IV had gone back to Calais and thence to England. He fought in 1485 at the Battle of Bosworth Field, where he was unhorsed personally by Richard III, and at the Battle of Stoke in 1487. He was made a Knight of the Garter and was called to parliament as Baron Cheyne.