Teenager Mary Carroll lived with her mother, sister, and brother, Dennis, in Pilot Grove, Missouri, at the beginning of the Civil War.
Although “Bleeding Missouri” had been a slave state in 1861, it voted to remain in the Union. Despite this, the state’s governor—a Southern supporter—offered guns and cannons to Confederate President Jefferson Davis. Union soldiers then seized the armory and the state’s capital to set up a Union government, creating great turmoil. Union troops arrested Missouri residents without charges. They took their horses and food.
Dennis Carroll was arrested in August of 1862 for trying to join the Confederate army. In March of 1863, he was released from an Alton, Illinois Federal prison.
Learning of Union plans to arrest a group of Missouri men intending to muster into the Confederate army, Mary rode through hard rain to warn them and lead them to safety.
In May of 1863, Dennis and a friend helped Confederate sympathizers raid a Federal militiaman’s home. After the Union man shot one of them, some set the home on fire. Though Dennis didn’t help set the fire, he was arrested, taken to Boonville, and sentenced to be shot to death.
Mary, 17, boarded with a family in Boonville to be near her younger brother. She sneaked a crowbar into him, at his request, with his lunch. His breakout attempt that night was unsuccessful.
Giving up meant her brother would die. She then set to work on making a key patterned like the jail door key. After several attempts, she made an iron key. It took days.
In the meantime, the Federal government ordered all Cooper county women to take an oath of allegiance. Mary complied, after making sure that nothing she was doing to save her brother violated that oath.
She gave the key to her brother. Unfortunately, it was too short.
A young Union soldier proposed marriage to Mary. She agreed—if he helped her brother break out of prison. He let her see the jail key and she made an impression of it on a book. He took it from her, but didn’t know she’d made another impression. She then created another key.
Meanwhile, the men awaiting execution tied leather around an earlier key out of desperation. The bits of leather made the key fit and they broke out of jail.
Suspicion immediately went to Mary, who was arrested during the search for the fugitives. In a letter to her mother, she asked which key Dennis used to escape. Union soldiers found her letter. She was interrogated by General Dodge and Colonel Catherwood.
The colonel remembered Mary’s question about helping her brother before taking the oath—it saved her.
Released and back at home, her relief didn’t last. Dennis was apprehended and killed by Union soldiers. They forced Mary’s family from their home.
After the war, Mary married a Confederate soldier, Thomas Brooks, and had six children. She wrote of her experiences in The Secret of the Key and Crowbar.
-Sandra Merville Hart
Cordell, M.R. Courageous Women of the Civil War, Chicago Review Press, 2016.