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 Jan Allertz (Recorder of Rotterdam), all state that Richard killed the princes before he seized the throne (thus before June 1483). De Commines' "Memoirs" (c.1500), however, identifies the Duke of Buckingham as the person "who put them to death". Only Mancini's account is truly contemporary, having been written in London before November 1483. The Croyland Chronicle and de Commines' account were written three and seventeen years later, respectively (and thus after Richard III's death and the accession of Henry VII). Markham, writing long before Mancini's account was discovered, argued that some accounts, including the Croyland Chronicle, might have been authored