Note: Australia is generally considered to be a continental landmass, rather than an island. If however one does count Australia among the islands it, not Greenland, would be the largest in the world (unless one also considered Antarctica an island).
... Charles became joint-king of Castile with his mother (who was insane), and also inherited Aragon, Navarre, Granada, Naples, Sicily, Sardinia, and Spanish America[?]. After ...