Siege of Leiden in 1574

According to historian Jeremy Bangs, director of the Leiden American Pilgrim Museum, the Pilgrims may have been influenced by watching the annual services of Thanksgiving for the relief of the siege of Leiden in 1574, while they were staying in Leiden. Now called Oktober Feest, Leiden's autumn thanksgiving celebration in 1617 was the occasion for sectarian disturbance that appears to have accelerated the pilgrims' plans to emigrate to America. Later in Massachusetts, religious thanksgiving services were declared by civil leaders such as Governor Bradford, who planned the colony's thanksgiving celebration and fast in 1623. The practice of holding an annual harvest festival did not become a regular affair in New England until the late 1660s.