On this date, the Irish Parliament ordered that October 23 be observed annually as a day of thanksgiving for what it called deliverance from the 1641 Irish Rebellion, which had begun exactly one year prior.
The rebellion, led by Irish Catholics against English and Protestant rule, sparked widespread violence and deepened sectarian divides. The observance institutionalized that division: for over a century, Protestant churches across Ireland held annual services on October 23, commemorating their survival and framing the uprising as proof of Catholic disloyalty.
This state-sponsored remembrance reinforced anti-Catholic sentiment and became a symbolic cornerstone in Protestant identity throughout the 18th century.