Richard III of England Wiki

Edmund Beaufort, 4th Duke of Somerset, 6th Earl of Somerset, 3rd Marquess of Dorset, 3rd Earl of Dorset (1438? – 6 May 1471) was an English nobleman, and a military commander during the Wars of the Roses, in which he supported the House of Lancaster.

After defeat in the Battle of Tewkesbury, Somerset and other Lancastrian leaders took refuge in Tewkesbury Abbey, but they were forced from sanctuary two days later. They were tried and executed immediately, at the Cross in the centre of Tewkesbury; Edmund and his younger brother John, who had fallen in the battle, were buried at the Abbey.

More information on the Wikipedia page [1].

See also Henry Beaufort, 3rd Duke of Somerset.