Fear as thick as the summer haze enveloped sultry Washington, D.C., on the morning of July 11, 1864. Fifty years after the British had torched the city, a foreign army had once again penetrated the United States capital. Within sight of the unfinished Capitol dome, clouds of dust rose from the orchards and pastures on the district’s northern outskirts as Confederate forces crossed the Maryland border and marched down the Seventh Street Pike.

Not even during the first days of the Civil War when Confederate bonfires could be seen burning across the Potomac River in Virginia had the national capital been in such peril. The Union Army had been so focused on tightening its noose on the Confederate capital of Richmond, that it had left its own seat of government vulnerable. General Ulysses S. Grant had moved the majority of the 23,000 soldiers assigned to defend Washington, D.C., to join in the siege of Richmond. All that remained was a ragtag bunch of 9,000 troops, mostly ill-trained soldiers recruited to serve no more than 100 days.

With the tide of the war turning against him, Confederate General Robert E. Lee needed a bold move and a bold man, Lieutenant General Jubal Early, to strike at the Union’s vulnerable heart. Lee dispatched the experienced and aggressive Early, whom he called “my bad old man,” and 15,000 troops north through Virginia’s Shenandoah Valley.

On July 5, Confederate forces crossed the Potomac River and set foot on Union soil for the third time during the Civil War. After a hard-fought victory on July 9 at Monocacy Junction, Early’s men marched toward Washington, D.C., as any man—able-bodied or not—was called upon to bolster the city’s defenses. Government clerks were issued muskets. Nearly 3,000 convalescing soldiers limped, hobbled and crawled out of hospital wards to man the fortifications.

As the fate of the jittery city hung in the balance, a calm, steady hand held a spyglass from a White House window. With the advancing enemy just five miles away, President Abraham Lincoln peered down the Potomac River, where a warship stood ready to evacuate him, and saw salvation. Rushing to his carriage as artillery shots thundered in the distance, Lincoln rode to the riverside wharves to personally greet the two battle-tested divisions of the Union Army’s 6th Corps that were hastily dispatched by Grant.

As a sign of his stiffened resolve, the commander-in-chief personally led his marching troops to the battle that had begun that morning at Fort Stevens. “Give the road for the President,” ordered the cavalry as Lincoln passed dead soldiers being carried away on stretchers and a stream of civilians fleeing for safety in the opposite direction.

Lincoln had always been a hands-on commander-in-chief, even personally test-firing rifles on the grassy expanses around the White House. Still, Confederate sharpshooters probably could not have believed their eyes when during the first afternoon of the Battle of Fort Stevens a lanky, bearded man in a dark suit and stovepipe hat emerged on the fort’s earthen parapets.

Discouraged by the elaborate defenses that had been erected and concerned about his tired soldiers wilting in the blistering heat, Early had held back on a major assault, but Confederate snipers trained to hit targets from distances of 800 yards or more were firing shots from perches in trees, cornfields and houses. One of those shots rang out and came close to striking the president, who was standing on the parapet surveying the enemy in the line of fire.

As John Hay, Lincoln’s private secretary, noted in his diary that night, ”A soldier roughly ordered him to get down or he would have his head knocked off.” While James Madison was in the vicinity of a battle when the British arrived in the city a half-century before, Lincoln might have been the only sitting American president to come under enemy fire while in office.

Thanks to years of work, Washington, D.C., had become one of the most-fortified cities in the world, and the defenses held strong after the first day of battle. Lincoln returned to the White House, “in very good feather” Hay reported, displaying little concern about the capital’s safety. Indeed, when Early awoke the next morning, he was crestfallen. Through his field glasses he could see the Union reinforcements that continued to arrive. He concluded that a full-out attack would be foolhardy but decided to keep fighting until the arrival of darkness that would provide cover for a retreat.

That afternoon, the president returned to the battlefield with his wife, Mary Todd Lincoln, in tow. The couple consoled the wounded soldiers and encouraged attending doctors. While the First Lady returned to their carriage, the president once again climbed the parapets, displaying “a remarkable coolness and disregard of danger,” according to General Horatio G. Wright. Suddenly a shot rang out and three feet to the right of Lincoln a Union surgeon crumbled to the ground with a severe wound to his leg. Only after repeated entreaties and threats to forcibly remove him did Lincoln’s subordinates succeed in convincing him to take cover.

Legend has it that Colonel Oliver Wendell Holmes, Jr., a future Supreme Court justice, barked, “Get down, you fool!” Lincoln left the battlefield unharmed, but not before giving his personal approval to shell houses being used as Confederate sniper nests.

As night fell, Early retreated and crossed back over the Potomac River two days later. The Confederacy never again threatened the capital. “We didn’t take Washington,” Early said, “but we scared Abe Lincoln like Hell.”