In July of 1864 Washington was in peril. While Union forces under General Grant closed in on Richmond, Confederate General Jubal Early had been sent north with 15,000 men to try to draw off as many Union troops as he could. Now he was a day’s march from Washington, and the troops that Grant had waited to send until the last minute might be too late.

To buy time Union General Lew Wallace scraped together 6,000 militia and garrison troops seasoned with a few combat veterans. They blocked the turnpike to Washington at the Monocacy River outside Frederick, Maryland.

The two forces met on July 9 in a battle that lasted until dusk. Numbers and veteran troops proved decisive for the Confederacy, and Wallace’s outnumbered men fell back to Baltimore. But the one day delay allowed reinforcements from Grant to arrive. Washington was saved.

But even without capturing Washington Early had succeeded in his mission. A full army corps had been withdrawn from the Petersburg front, and Richmond would survive another nine months. But in August in the Thomas house on the Monocacy battlefield, Grant would set down with a brash cavalry general named Philip Sheridan and plan what would eventually be the total destruction of Early’s army.