John Wenlock, 1st Baron Wenlock KG (died 1471) was an English soldier, courtier and politician. He fought on the sides of both the Yorkists and the Lancastrians in the Wars of the Roses. One historian has gone so far as to call him "Prince of Turncoats."
His service to the Crown is also reflected in his employment as a member of some 18 embassies in the 1440s and 1450s. He was knighted in 1449. It appears to have been at one such embassy that he came into contact with the Duke of York and the Earl of Warwick, and he became a supporter of the latter.
During the Wars of the Roses, Wenlock initially fought for the House of Lancaster in the First Battle of St Albans on 22 May 1455, but his relationship with Warwick led him to subsequently change sides, and it was as a Yorkist that he served as Speaker of the House of Commons later that year in the parliament of 1455. By the Battle of Blore Heath in 1459 Wenlock fought for the House of York. He also fought under the Yorkist banner in the Battle of Mortimer's Cross, the Second Battle of St Albans and the Battle of Towton, all in what is referred to as the first phase of the War of the Roses.
Having successfully besieged the Tower of London for Edward of York, he was part of the latter's triumphal entry into London in 1461 and was elected a knight of the Garter a few days after. Later in the year he received appointment as Chief Butler of England and was made Baron Wenlock. In 1464 he helped Lord Hastings capture Dunstanburgh Castle.
Wenlock died without issue, and his title died with him.
A longer biography on the Wikipedia page