In the six days following the fall of Fort Sumter, President Lincoln had called on volunteers to put down the rebellion and to defend Washington City. Among those heeding the call were the green troops of the 6th Massachusetts Infantry regiment. Their railroad journey to the capital took them through New York, then Philadelphia. Their next stop was Baltimore, where Northern soldiers were openly despised.

The raw boys from Boston numbered about one thousand, filling ten railcars. Since Baltimore offered no direct rail link between Philadelphia and Washington, the cars had to be derailed at one station and pulled by teams of horses along the streetcar line to the other. The streetcar line was on Pratt Street, Baltimore’s main thoroughfare. The resentful citizens gathered on Pratt to watch this unwelcome Yankee procession.

Soon Pratt Street was choked with humanity as people lined either side to watch this procession. The reluctant horses plowed forward as the tension increased with each passing car. Seven had gone by, and the eighth was about to turn onto Pratt. The sidewalks were filled beyond capacity, and the swelling crowd spilled into the street. Onto the rail line. Blocking the path of the approaching car.

The crowd noise dwindled. The faint clip-clop of horse hooves could be heard in the distance, and people jostled for position on the street. The street was suddenly calm. All eyes watched the car as it rounded the corner onto Pratt. The car moved slowly, as if part of a funeral procession.

When the railcar came into the crowd’s full view, the din of hatred resumed. The horses balked at the sight of hundreds of angry people blocking their path and refused to move. The ninth and tenth cars behind the eighth were halted as well. The last three hundred men of the 6th Massachusetts were now stranded on Pratt Street, with an irate mob between them and the train station.

Vile curses echoed through Baltimore. The ranking officer of the Massachusetts men ordered them to load their muskets and file into the street. The soldiers’ only chance was to leave the stopped railcars and try for the station on foot. To get there, they would have to march directly through the incensed mob.

Unlike the warm receptions they received in New York and Philadelphia, the soldiers were met with curses, shoves, rocks, and spit as they stepped out into Baltimore. They were ordered to form a line of march and proceed at the quickstep, and they used their muskets to push their way through the crowd. When they met resistance, they dropped their heads and pushed harder, as if braving a fierce Boston storm.

While people were knocked down, stepped over, and shoved every which way, one man towered over the rest. He stood nearly seven feet, and was as thick as he was tall. Robert Gregg stepped into Pratt Street, pushing people out of his path as if wading through a calm stream. He moved against the swarm’s tide, going into the street as people were being shoved to the sidewalk. His small beady eyes were fixed on the advancing troops. There was no humanity in these cold eyes.

Gregg thrust his right hand deep into his coat pocket and felt his .44-caliber Adams & Deane, a double-action five-shooter imported from England. Gregg stepped to within five feet of the front line and cocked the weapon. The Massachusetts boys kept their heads down as they continued forcing themselves through the horde. They did not see Gregg approaching.

Gregg fired the revolver right through his coat pocket.

The gunshot was muffled by the din of the crowd. Only when a private in the front line fell back did people realize what had happened. The private’s cap fell off, revealing his long blonde hair. The boy could not have been older than seventeen. Two other privates pulled him toward the sidewalk and lay him down. A low gasp hummed in the street. All was still as the looks of terror on the faces of the Union boys turned to rage.

At the sound of the order, the soldiers presented arms. People jostled frantically as the order was given to aim and fire. Aiming wasn’t necessary. It was impossible to miss. The twenty soldiers in the front line opened fire at point blank range.

As the smoke cleared, the Massachusetts men passed through the swath they had cut through the crowd. They were ordered forward at the double-quick.

For those not hit by bullets, their fury became hysteria. They charged the troops, hurling stones, bricks, bottles, and anything else they could find. When the soldiers turned and threatened to fire again, the mob stepped back far enough to let them pass. Then they chased the troops all the way to Camden Street.

The soldiers raced to the train station, where the rest of the 6th Massachusetts was waiting. Upon hearing what had happened, the colonel threatened to march back into Baltimore and declare it an open city. The mob grudgingly dispersed, while Pratt Street reeled from the carnage.

Robert Gregg stood in a nearby alley and watched the aftermath of the bloodbath he had incited. He had easily dodged the volley of soldier fire by shoving his way through the smaller, less fortunate members of the crowd. Gregg leaned back into the shadows and saw the remnants of the mob cursing the soldiers and the Union cause, calling on God for retribution. A rat scurried past Gregg’s foot, and he kicked it away as he glanced down the other end of the alley. The wagon was waiting.

The wagon was hitched to a team of horses, and the driver’s eyes met Gregg’s. With a mutual nod, Gregg climbed into the back, lay down, and covered himself with a tarpaulin. The driver, a burly man with a thick black mustache, snapped the reins, and the horses began forward. They avoided Pratt Street as they headed for the Liberty complex.