The exhibit will run from April 23 until September 6, 2009 in honor of the 500th anniversary of Henry's accession to the throne. The mystery of why there was no depiction of the final battle had baffled historians for centuries.
"'Everybody just assumed that the end of the siege had not been done,' Peter Barber, head of map collections at the British Library, told the Observer. But due to a cataloguing error the existence of a fourth drawing had gone unnoticed. It only came to light when Barber began re-cataloguing the manuscripts of Sir Robert Cotton, which had been left to the nation by his grandson, Sir John Cotton, in 1702 and passed to the British Museum on its founding in 1753."