Among the many militia regiments that responded to President Lincoln's call for troops in April 1861 was the First Minnesota Infantry. As the First Union regiment to volunteer for three years of service, the First Minnesota fought at the battles of Bull Run, Antietam and Fredericksburg. It was, however, during the Battle of Gettysburg that the First Minnesota played a significant role in American military history. On the morning of July 2, 1863, the First Minnesota, along with the other units of the II Corps, took its position in the center of the Union line on Cemetery Ridge. Late in the day, the Union III Corps, under heavy attack by the Confederate I Corps, collapsed creating a dangerous gap in the Union line. The advancing Confederate brigades were in position to breakthrough and then envelope the Union forces. At that critical moment, the First Minnesota was ordered to attack. Advancing at double time, the Minnesotans charged into the leading Confederate brigade with unbounded fury. Fighting against overwhelming odds, the heroic Minnesotans gained the time necessary for the Union line to reform. But the cost was great. Of the 262 members of the regiment present for duty that morning, only 47 answered the roll that evening. The regiment incurred the highest casualty rate of any unit in the Civil War. The gallant heritage of the First Minnesota is carried on by the 1st and 2nd Battalions, 135th Infantry, Minnesota Army National Guard.