sentences:  As noted above, Richard had married Anne de Mortimer, this giving their son (and the House of York), through Lionel of Antwerp, a more senior claim than that of both the House of Lancaster, which descended from a younger son than Lionel, and the House of Tudor, whose legitimized Beaufort ancestors had been debarred from the throne.In 1460 Richard, 3rd Duke of York claimed the throne on this basis, but an Act of Accord meant he instead became heir.However he was killed later that year, causing his son Edward to take over.