On May 24, 1861, Elmer E. Ellsworth, a 24-year-old Army colonel and close friend of President Abraham Lincoln, became the first Union officer killed during the Civil War. According to the 2003 spring/summer edition of Washington History magazine, Ellsworth, of the New York Zouaves Regiment, was shot and killed when he removed a Confederate flag from the roof of the Marshall House hotel on King Street in Alexandria.

The day before, a secession convention in Virginia ratified a decision for the commonwealth to secede from the Union. Ellsworth and his regiment were among the first to arrive in the District to protect the capital city following the previous month’s bombardment of federal troops at Fort Sumter near Charleston, S.C. They also occupied adjacent territory across the Potomac River in Virginia, including the city of Alexandria.

Ellsworth would meet his fate that night at the hands of Marshall House innkeeper and fervent defender of slavery, James W. Jackson. Smithsonian magazine wrote that Ellsworth had approached the inn with only four soldiers and managed to take down its 8 foot by 14 foot Confederate flag, which could be seen from the White House with the aid of binoculars. When he returned to the main floor, Jackson fired his shotgun, killing Ellsworth. One of Ellsworth’s men, Cpl. Francis Brownell fired back, fatally injuring Jackson.

A reporter for the New York Tribune was on the scene and quickly dispatched news of Ellsworth’s death. According to Washington History, his assassination sent Washingtonians “into a state of shock over the news.”

Ellsworth was more than just a Union officer. Smithsonian wrote that he worked as a patent agent in Rockford, Ill., and studied law in Chicago, where he also served in the National Guard. In 1860, Ellsworth became friends with Lincoln while working at his Springfield law office and accompanied the new president-elect when he moved to D.C. the following year.

Upon learning of Ellsworth’s death, Lincoln reportedly cried out, “My boy! My boy! Was it necessary this sacrifice should be made?” Equally distraught by their commander’s death, Ellsworth’s troops threatened to burn the city of Alexandria that night. Instead, Union authorities put them to work on building Fort Ellsworth, which overlooked the city, which would remain occupied by Union forces through the duration of the war.

According to the National Portrait Gallery’s current exhibition, “The Death of Ellsworth,” his body was first brought to the Washington Navy Yard and later to the East Room of the White House upon Lincoln’s request. Ellsworth was buried in his hometown of Mechanicville, N.Y., where thousands came to pay their respects.

His esteem lived on among the 44th New York Volunteer Infantry Regiment nicknamed Ellsworth’s Avengers. His true avenger, Brownell, later received the Medal of Honor, and “Remember Ellsworth!” became a battle cry for the Union. But both sides emerged with their own version of the war’s first martyr. In the South, Jackson was praised in an 1862 book, Life of James W. Jackson, The Alexandria Hero.

Image courtesy Library of Congress Prints and Photographs Division