We all know of Marathon Monday as the commencement of the annual Boston Marathon but sometimes overlook the fact that it’s also Patriots’ Day. Also celebrated in Maine and Wisconsin, Patriots’ Day is meant as a day of reflection and commemoration of Battles of Lexington and Concord on April 19, 1775. The U.S. Army’s 3rd U.S. Infantry Regiment will undertake a series of events and celebrations in and around Boston in honor of the holiday.

Aptly nicknamed “The Old Guard” for being the oldest active regiment in the army, the 3rd Infantry Regiment will split time between Boston, Lexington and Concord between April 19 and April 21 for a bevy of dedicatory endeavors.

The primary responsibilities of the regiment are to perform ceremonial acts and memorial affairs to honor fallen military brethren while representing the army.

Events will be peppered with performances from the likes of The U.S. Army Drill Team, the U.S. Army Old Guard Fife and Drum Corps, and the Commanders-in-Chief’s Guard. Absolutely everything will be free and open to the public.

The history of the regiment dates back to 1784, when it was formed. It received its conventional nickname in 1847, according to the army, when General Winfield Scott designated it “The Old Guard” during a victory parade in Mexico City.

Scott was essentially the action hero of his day, commanding forces in the War of 1812, the Black Hawk War prior to the Mexican-American War. He marched his troops through Mexico, landed at the coast of Veracruz and made his way to the capital inland.

“Fifty campaign streamers attest to the 3d Infantry’s long history of service, which spans from the Battle of Fallen Timbers to World War II and Vietnam,” notes the army’s bio.