The Last of the Barons, Book IX by Edward Bulwer-lytton

The events that followed the king's escape were rapid and startling. The barons assembled at the More, enraged at Edward's seeming distrust of them, separated in loud anger. The archbishop learned the cause from one of his servitors, who detected Marmaduke's ambush, but he was too wary to make known a circumstance suspicious to himself. He flew to London, and engaged the mediation of the Duchess of York to assist his own. [Lingard. See for the dates, Fabyan, 657.]

The earl received their joint overtures with stern and ominous coldness, and abruptly repaired to Warwick, taking with him the Lady Anne. There he was joined, the same day, by the Duke and Duchess of Clarence.