Kelly finds evidence of Yorkist bias in the earlier tetralogy. "1 Henry VI" has a Yorkist slant in the dying Mortimer's narration to Richard Plantagenet (later Duke of York). Henry VI is weak and vacillating and overburdened by piety; neither Yorkists nor Queen Margaret think him fit to be king. The Yorkist claim is put so clearly that Henry admits, aside, that his own is weak—"the first time," notes Kelly, "that such an admission is conjectured in the historical treatment of the period". Shakespeare is suggestively silent in Part 3 on the Yorkist Earl of Cambridge's treachery in Henry V's reign. Even loyal Exeter admits to Henry VI that Richard II could not have resigned the crown legitimately to anyone but the heir, Mortimer. Edward (later IV) tells his father York that his oath to Henry was invalid because Henry had no authority to act as magistrate.