Today is the 150th anniversary of the beginning of the Battle of Gettysburg, the pivotal battle of the Civil War and the largest battle ever fought in the Western Hemisphere. A key figure on the first day was the man pictured above, John Buford, a Union cavalry general.

In some ways Buford was responsible for the entire battle. Scouting ahead of the main Union army on June 30, 1863, Buford and his key commanders rode into Gettysburg and realized that some Confederate troops were approaching. Buford correctly ascertained that the main body of the Southern army was behind them and that Gettysburg was a key location. He deployed his forces near the town to try to prevent the Confederates from gaining the high ground.

On Wednesday, July 1, in the morning, Buford’s cavalry–now dismounted–faced several units under the command of Confederate Gen. Henry Heth. Although Buford’s forces were badly outnumbered, he managed to hold them off until Union reinforcements arrived. Sporadic battles took place over the rest of the day, but Buford’s defense of the high ground became the key factor of the battle.

Sadly, Buford himself didn’t live long after the battle. He contracted a disease, probably typhoid, and died on December 16, 1863. Lincoln promoted him to Major General on his deathbed.

You can read more about the first day of the Battle of Gettysburg here.