When a tenant in chief, the people who held land directly from the king, died with his/her heir underage - under 21 if male, 14 if female and married, or 16 if female and unmarried - the king owned the rights to the heir's marriage. He either arranged the heir's marriage himself, or sold the rights to someone else. Men owned their own marriage rights when they came of age at 21
When Theobald de Verdon died on  July 1316, he left his three daughters from his first marriage to the late Maud Mortimer (d. 1312), and his second wife Elizabeth (de Clare) de Burgh was a month pregnant with his fourth daughter. On , Edward II granted the marriage of Theobald's eldest daughter Joan (b. August 1303) to Sir William Montacute, who waited until Elizabeth de Burgh had given birth to her daughter Isabella de Verdon on 21 March 1317. If Isabella had been a boy, she would have become Theobald's sole heir from the moment of birth and would have disinherited Theobald's three living daughters, but as it was, the birth of a girl meant that Theobald's estate would be divided into four equal portions for his four daughters. In the knowledge that Joan de Verdon would inherit a quarter of the sizeable inheritance, William Montacute married her off to his eldest son John (b. c. late 1290s) on 28 April 1317, a few weeks after the birth of Joan's half-sister. If Joan had been disinherited by the birth of a half-brother, William would most probablyn not have 'wasted' her on his eldest son but would have married her off to another of his relatives, probably one of his younger sons or a nephew.
In March 1352, Thomas Staple of Southwark offered his 20-year-old ward John Amory of Leicestershire (b. November 1331) a choice between two brides: Alice Cleet of Berkshire or Isabel St Albans of Surrey. John 'utterly refused both, and of his own accord' married Alianor Baryngton instead. An inquiry found that Thomas Staple had lost £200 from John's marriage, and John acknowledged that he owed Thomas this amount. William Cantilupe or Cauntelo or Cantelewe was born in 1293. Sometime before 15 January 1314 when he was 20, his stepmother Eva, who owned the rights to his marriage, also offered him a choice between two brides: Joan, daughter of John de Grey, or Margaret, daughter of Robert de Strenle. William 'expressly answered and said that he would not have any woman to wife'. He was told to pay Eva the value of his marriage, and died at an unknown date after November 1320, having apparently never married.