Bleeding Kansas was a border war on the Kansas-Missouri border. It started with the Kansas–Nebraska Act of 1854. It continued into the American Civil War (1854–1861). It was an ugly war between groups of people who had strong beliefs about slavery. The term was first coined by Horace Greeley of the "New York Tribune". He used it to describe the violence happening in the Kansas territory during the mid to late 1850s. Three different groups were fighting for power in Kansas at the time. These were those who were pro-slavery, abolitionists and free-staters. Bleeding Kansas, fought over the issue of slavery, was a precursor of events to come in the American Civil War.