It occurred between antiwar "Copperhead" Democrats (the largest party in Maryland) and other Confederate sympathizers on one side, and on the other, members of Massachusetts and Pennsylvania state militia regiments en route to the national capital at Washington who had been called up for federal service.

[3] Lincoln's opponents were infuriated (and supporters disappointed) when the president-elect, fearing an infamous rumored assassination plot, traveled secretly through the city in the middle of the night on a different railroad protected by a few aides and detectives including the soon-to-be famous Allan Pinkerton in February en route to his inauguration (then constitutionally scheduled for March 4) in Washington, D.C.

In fact, prior to Lincoln's demand for 75,000 soldiers with which to invade the South, Virginia, North Carolina, and Arkansas had elected secession delegations which had voted to remain in the Union and Tennessee had held a referendum of the people to determine whether or not to elect a secession delegation, and had voted by about 2/3 majority to not even consider the matter.

When Fort Sumter fell on April 13, President Lincoln sent telegraphs followed by letters to the all the governors of states that had not seceded, calling for 75,000 troops with which to re-possess U.S. property in the South.

Sympathetic Marylanders, who had supported secession ever since John C. Calhoun spoke of nullification, agitated to join Virginia in leaving the Union.

[7] New militia units from several Northern states were starting to move south, particularly to protect Washington, D.C., from the new Confederate threat in Virginia.

[9] They were joined by several regiments of regular United States Army troops under John C. Pemberton (later the Confederate general and commander at the siege of Vicksburg, Mississippi, whose surrender in July 1863 resulted in the first split of the Confederacy) returning from duty on the western frontier.

Seven hundred "National Volunteers" of Southern sympathizers rallied at the Washington Monument and traveled to the station to confront the combined units of troops, which unbeknownst to them were unarmed and had their weapons unloaded.

[13] According to his later report, Jones went through the railroad cars and gave this order: The regiment will march through Baltimore in column of sections, arms at will.

[14]Indeed, as the militia regiment transferred between stations, a mob of anti-war supporters and Southern sympathizers attacked the train cars and blocked the route.

[24][25][26][27] The same day, after the attack on the soldiers, the office of the Baltimore Wecker, a German-language newspaper, was completely wrecked and the building seriously damaged by the same mob.

[31] On July 10, 1861, a grand jury of the United States District Court indicted Samuel Mactier, Lewis Bitter, James McCartney, Philip Casmire, Michael Hooper and Richard H. Mitchell for their part in the riot.

[32] After the April 19 riot, some small skirmishes occurred throughout Baltimore between citizens and police for the next month, but a sense of normalcy returned as the city was cleaned up.

However, as Lincoln remarked to a peace delegation from the YMCA, Union soldiers were "neither birds to fly over Maryland, nor moles to burrow under it".

[33] On the evening of April 20 Hicks also authorized Brown to dispatch the Maryland state militia for the purpose of disabling the railroad bridges into the city—an act he would later deny.

Since Annapolis, the capital, was occupied by Federal troops, and Baltimore was harboring many pro-Confederate mobs, Hicks directed the legislature to meet in Frederick, in the predominantly Unionist western part of the state.

[40] Chief Justice Roger B. Taney, also a native of Maryland, ruled on June 4, 1861, in ex parte Merryman that Lincoln's suspension of habeas corpus was unconstitutional; but Lincoln ignored the ruling, and in September when Baltimore newspaper editor Frank Key Howard, Francis Scott Key's grandson, criticized this in an editorial he too was imprisoned without trial.

[40] A man supposed to be a Maryland State Militia soldier was detained in Fort McHenry, and Judge Giles, in Baltimore, issued a writ of habeas corpus, but Major W. W. Morris, commander of the fort, wrote back, "At the date of issuing your writ, and for two weeks previous, the city which you live, and where your court has been held, was entirely under the control of revolutionary authorities.

Within that period United States soldiers, while committing no offense, had been perfidiously attacked and inhumanly murdered in your streets; no punishment had been awarded, and, I believe, no arrests had been made for these crimes; supplies of provisions intended for this garrison has been stopped; the intention to capture this fort had been boldly proclaimed; your most public thoroughfares were daily patrolled by large numbers of troops, armed and clothed, at least in part, with articles stolen from the United States; and the Federal flag, while waving over the Federal offices, was cut down by some person wearing the uniform of a Maryland soldier.

To add the foregoing, an assembly elected in defiance of law, but claiming to be the legislative body of your State, and so recognized by the Executive of Maryland, was debating the Federal compact.

"[42] Just before daybreak on June 27, soldiers marched from Fort McHenry on orders from Major General Nathaniel P. Banks, who had succeeded Cadwalader as commander of the Department of Annapolis, and arrested Marshal George P. Kane.

[46] The poem was later set to "Lauriger Horatius" (the tune of O Tannenbaum), a melody popular in the South, and referred to the riots with lines such as "Avenge the patriotic gore / That flecked the streets of Baltimore".

[50] On September 17, 1861, the day the legislature reconvened to discuss these later events and Lincoln's possibly unconstitutional actions, twenty-seven state legislators (one-third of the Maryland General Assembly) were arrested and jailed by federal troops, using Lincoln's suspension of habeas corpus, and in further defiance of the U.S. Supreme Court Chief Justice's ex parte Merryman ruling.