Cillian Keevan (1807-1863) was an Irish immigrant to the United States who settled in New York City during the mid-19th century. In 1863, he snuck into a performance of Uncle Tom's Cabin by Harry Watkins, where nativist leader William Cutting and many of his xenophobic Natives gang members were mocking Abraham Lincoln and the Union. As the rowdy crowd cheered on the Natives throwing vegetables at Watkins (who was playing Lincoln), Keevan shouted "For the blood of the Irish" and shot Cutting in the side. However, Amsterdam Vallon tackled Keevan and shot him in the chest with his own gun. Cutting attempted to interrogate Keevan, threatening to teach the Irishman the English language with his knife (saying that English was the only language allowed in America), but Keevan continued to pray in Latin until he bled to death, having been unable to reveal who he was working for. Cutting believed boss William M. Tweed to be responsible, as Tweed had cryptically warned Cutting that the rising tide of Irish immigrants would eventually overtake him.