Princes in the Tower act stated that Edward IV and Elizabeth Woodville's marriage was invalid because of Edward's pre-contract of marriage with Lady Eleanor Butler. Gloucester was crowned King Richard III of England on 3 July. The declaration of the boys' illegitimacy has been described by Rosemary Horrox as an ex post facto justification for Richard's accession. Dominic Mancini, an Italian friar who visited England in the 1480s and who was in London in the spring and summer of 1483, recorded that after Richard III seized the throne, Edward and his younger brother Richard were taken into the "inner apartments of the Tower" and
Princes in the Tower of Scotland. After a failed attempt to invade England he was captured. He retracted his claims, was imprisoned and later executed. Many modern historians believe he was an imposter, whose supporters accepted his claim for political reasons. The fact that two persons claimed to be Richard led the 18th century writer Horace Walpole to argue that Richard had in fact escaped death, and that Warbeck genuinely was Richard, a view also supported by Malcolm Laing. Walpole, however, later retracted his views and stated that he now believed the princes to have been murdered by Richard III to secure his hold