It was through Anne Mortimer's lineage that the Yorkists derived their main claim to the throne.

Following Edmund of Langley's death in 1402, his son Edward succeeded to the dukedom but had no issue before he was killed at the Battle of Agincourt in 1415. His other son Richard had been executed for treason earlier in the same year following his involvement in the Southampton Plot to depose Henry V in favour of Edmund Mortimer,