As Henry's predecessor, Edward III, had recognised Mann as an independent kingdom, Henry IV did not directly claim the Manx throne, but instead proclaimed that he had acquired the island by right of conquest, which in international legal theory at that time erased any existing constitutional arrangements.
Following Percy's treasonous rebellion, Henry IV granted the suzerainty of the Isle of Man, on similar terms but only for the term of his life, to Sir John Stanley in 1405 [REF].