Following the Ludlow Massacre on 20 April 1914, strikers launched numerous attacks of both coordinated and spontaneous natures against mining operations, strikebreakers, and the National Guard in what is known as the Ten-Day War. One of the attacks was launched against Southwestern Mine Co.'s Empire Mine on 22 April, where armed strikers forced non-striking miners and their families into the mine and began an all-night siege outside. After negotiation led by Aguilar's mayor and a church minister named McDonald, the strikers abandoned the siege before fatalities on either side were reported.