Complex sentence: The 10th Ohio Infantry was organized at Camp Harrison near Cincinnati, Ohio, and mustered in for three months'service on 7 May 1861, under Colonel William Haines Lytle, in response to President Lincoln's call for 75,000 volunteers.
Split into simpler sentences: The 10th Ohio Infantry was organized at Camp Harrison near Cincinnati, Ohio, and assembled for three month's service on 7 May 1861, under Colonel William Haines Lytle. This was in response to President Lincoln's call for 75,000 volunteers.