According to Philip Melanchthon, 31 October 1517 was the day 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 and other experts on the subject argue that Luther may have chosen All Hallows' Eve on purpose to get the attention of common people, although that has never been proven.

This has been verified; it is now regarded as the start of the Reformation alongside the unconfirmed (Melanchthon appears to be the only source for that) nailing of the Ninety-five Theses/grievances to All Saints' Church's door on the same date.

The Roman Catholic Church recognized it only recently, and often sends its official representatives in ecumenical spirit to various commemoration events held by Protestants.

In addition, countries like Switzerland and Austria provide specifics in laws pertaining to Protestant churches, while not officially proclaiming it a nationwide holiday.

In 1516–1517, Johann Tetzel, a Dominican friar and papal commissioner for indulgences, was sent to Germany to raise money to rebuild St Peter's Basilica in Rome.

"[3] Luther objected to a saying attributed to Johann Tetzel that "As soon as the coin in the coffer rings, the soul from purgatory [also attested as 'into heaven'] springs.

[citation needed] According to Philipp Melanchthon, writing in 1546, Luther "wrote theses on indulgences and posted them on the church of All Saints on 31 October 1517", an event now seen as sparking the Reformation.

[5] Some scholars have questioned Melanchthon's account, since he did not move to Wittenberg until a year later and no contemporaneous evidence exists for Luther's posting of the theses.

[citation needed] The parish order for the New Church in Regensburg states that the Reformation of the city is to be observed the first Sunday after 15 October, every year.

Due to ecumenical movements, some other Christian groups now tend to acknowledge or co-participate in church services celebrating Reformation Day.

That includes the Roman Catholic Church, as well as various Protestant denominations that are neither Lutheran or Reformed, i.e. those that lack a direct connection to religious events of the 16th century Europe.

In 1817, the victory over Napoleon influenced the celebrations and led to the anniversary's national orientation: Luther became the German hero and the ideal role model for the bourgeoisie; he was depicted time and again in festive parades and popular prints.

[citation needed] The 1817 anniversary was largely nationalist in outlook, being impacted by some of the most important events in human history: the French Revolution, the Napoleonic Wars, and political and territorial rearranging of Europe with the Congress of Vienna.

[23] Representatives from the Anglican Communion, Baptist World Alliance, Eastern Orthodox Church, and Salvation Army also participated in the predominantly Lutheran and Roman Catholic event.

[24] Pope Francis, in a joint statement with Bishop Munib Younan, stated that "With gratitude we acknowledge that the Reformation helped give a greater centrality to sacred Scripture in the Church's life".

These states are Baden-Württemberg,[28] Bavaria,[29] Berlin,[30] Bremen,[31] Hamburg,[32] Hesse,[33] Lower Saxony,[34] North Rhine-Westphalia,[35] Rhineland-Palatinate,[36] Saarland,[37] and Schleswig-Holstein.

With the increasing influence of Protestantism in Latin America (particularly newer groups such as various Evangelical Protestants, Pentecostals or Charismatics),[47] it has been declared a national holiday in Chile in 2009,[48] and in Peru in 2017.

[52] Reformation Day (Reformationsfest) was celebrated in Leipzig in Johann Sebastian Bach's time with a service, for which he composed church cantatas, including Gott der Herr ist Sonn und Schild, BWV 79 and Ein feste Burg ist unser Gott, BWV 80.

[citation needed] Although not shaped by Luther's doctrine, Calvinist churches throughout the world do not regard the Reformation Day as less important, and celebrate it in a similar manner to Lutherans.

Reformed theology first emerged in 1516 with Huldrych Zwingli in Switzerland who decided to participate in this European-wide discussion after seeing Luther's postulates; all this would not have happened without the events of 31 October 1517.