John Lackland was an Angevin king of England (1199-1216 AD) and was brother to his predecessor, Richard I. He had many failures, losing his French territories (hence the nickname "Lackland" or "Sans Terre"), being excommunicated by the Pope and being forced to ratify the Magna Carta. He is also known as the Prince John of the Robin Hood stories and didn't have a good reputation with his populace. However, he did manage to maintain a number of the reforms instituted by his father, Henry II.
He married twice. First to Isabella (also known, variously, as Avice or Advisa, Hawise, Joan and Eleanor), daughter of William, Earl of Gloucester, with no children. Second to Isabella daughter of Aymer Taillefer, Count of Angouleme, with the children Henry, Richard, Isabella & Eleanor. He also had an illegitimate daughter, Joan, whom he married to Llewelyn the Great of Wales, thereby initiating the English claim to sovereignty over Wales.
He was a loser if there ever was one. Not only was he plagued with the problems both he and Richard I created, but near the end of his life, his personal belongings were misplaced in a soggy bog called Wash. Hereafter, he is called "The King who lost his clothes in the Wash".