The Basilica of Collemaggio was founded in 1288 by Pietro da Morrone, later Pope Celestine V, who rejected the papal throne. Declared a national monument in 1902, the basilica is the site of an annual jubilee, the first in history, instituted by the Bull of Forgiveness in 1294. There is also a Holy Door to one side, which opens only for 24 hours a year, on 28–29 August. In 1327, the basilica became the burial place of Pope Celestine V, with a special mausoleum built to house his remains. The violent earthquake in 2009 caused extensive damage to the ancient Basilica, whose rebuilding is still in progress.