Reformation Day offers a theological reason for its observance of Reformation Day, stating that: Alongside Reformation Day, many Protestant Churches observe All Hallow's Eve on October 31, the vigil of All Saint's Day. Reformation Day Reformation Day is a Protestant Christian religious holiday celebrated on 31 October, alongside All Hallows' Eve (Halloween) during the triduum of Allhallowtide, in remembrance of the onset of the Reformation. According to Philip Melanchthon, 31 October 1517 was the day German monk Martin Luther nailed his "Ninety-five Theses" on the door of the All Saints' Church in Wittenberg, Electorate of Saxony in the Holy Roman Empire. Historians
All Saints' Day the past, did not celebrate All Hallows Day on this 1 November date, as extant historical documents attest that the celebration in Ireland took place in the spring: "... the "Felire" of Oengus and the "Martyrology of Tallaght" prove that the early medieval churches [in Ireland] celebrated the feast of All Saints on 20 April." A November festival of all the saints was already widely celebrated on 1 November in the days of Charlemagne. It was made a day of obligation throughout the Frankish empire in 835, by a decree of Louis the Pious, issued "at the instance of Pope