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 goal. This theory formed the basis of Sharon Penman's historical novel, "The Sunne in Splendour". Henry VII (Henry Tudor), following his seizure of the crown, executed some of the rival claimants to the throne. One who was either executed or died in captivity was John of Gloucester, illegitimate son of Richard III. Henry was out of the country between the princes' disappearance and August 1485, thus his only opportunity to murder them would have been after his accession in 1485. Pollard suggests Henry (or those acting on his orders) is "the only plausible alternative to Richard III." The year after