The history of the "Kingdom" of Redonda is shrouded in doubt and legend, and it is difficult to separate fact from fiction. According to one of several different versions of the story, Matthew Dowdy Shiell, a banker from Montserrat, claimed the island when his first son, Matthew Phipps Shiell, was born. Supposedly he felt he could legitimately do this, because it appeared to be the case that no country had officially claimed the islet as territory. Sheill senior also is said to have requested the title of King from Queen Victoria and as legend has it, she granted it to him as long as there was no revolt against colonial power.  However, the whole story appears to have originated decades years later with the son, known as M.P. Shiel, a fantasy and science fiction writer, and it is possible that some, or most, or possibly all of the story, may be pure invention.
In any case, again according to one version of the story, M.P. Shiel in later life gave the title, and the rights of his work, to the writer John Gawsworth, who seems to have sold the title several times, due to permanent bankruptcy. Gawsworth in turn is considered to have bestowed the title, and the rights to his and Shiel's work, to Jon Wynne-Tyson.
Tired of the problems of the kingdom, Wynne-Tyson supposedly resigned his title in 1997, when he decided to name Javier Marías as his successor (and bearer of the rights of the work of both Shiel and Gawsworth). Wynne-Tyson chose to do this because of the positive way in which Marías portrayed Gawsworth in his novel Todas las almas (published in English as All Souls).
Why do so many different people claim to be King of Redonda? Part of the incentive to be the recognized sole "King" of Redonda might be because of the rights to Gawsworth's literary sales, but a greater part of the appeal seems to be simply the lure of the fabled and ridiculous, and the joy of telling tall tales.