Religious and historical commemorations for October 20

October 20, 2026, marks several religious and historical commemorations. In the Orthodox calendar, the day honors Saint Artemie, a commander in the army of Emperor Constantine who was martyred under Emperor Julian the Apostate. Saint Artemie is traditionally venerated as a healer of mental illnesses and a protector against temptation. The calendar also commemorates Saint Gherasim of Kefalonia.

Historically, the date marks various global events, including the 1803 ratification of the Louisiana Purchase by the United States Senate and the 1818 treaty establishing the border between the United States and the United Kingdom at the 49th parallel. Other notable historical milestones include the 1600 victory of the Tokugawa family at Sekigahara in Japan and the 1740 accession of Maria Theresa to the throne of Austria.