Henry Tudor dies/Richard III fends off challenges to his reign. John II of Portugal, from Philippa Lancaster's line, becomes the primary anti-Richard claimant but doesn't have much interest pressing the claim.
Jorge de Lencastre, illegitimate son of John II, is courted by what Lancastrians are left and decides to invade England with a Portuguese/mercenary host ca. 1505. The Lancastrians remnant, foreigners, and other local opponents of Richard III gather to him. They defeat and kill Richard in the field. King George I of the House of Avis reigns in England.