Did you know that a woman signed the Declaration of Independence? Yes, you read that right. Mary Katherine Goddard’s name appears beneath those of our Founding Fathers.

Mary Katherine was born in New London, Connecticut, on June 16, 1738, to Dr. Giles Goddard, a physician and postmaster, and Sarah Updike Goddard. Mary Katherine was one of only two of their four children to live to adulthood. (No photos of her remain, but there is one that is often wrongly identified as her.)

Her mother tutored her in reading and math and then she attended New London’s public school, which taught girls for one hour a day when the boys’ lessons were over. There she learned Latin, French and science.

In 1755, Giles Goddard fell ill and was too sick to work, so her brother, William (then 15), went to New Haven to serve as a printer’s apprentice. Seven years later, Giles died and Mary Kathrine and her mother joined William in New Haven, where he owned a printing shop. Not long after, they founded Rhode Island’s first newspaper, the Providence Gazette.

William, always seeking a new adventure, moved from Providence to Philadelphia to Baltimore—starting newspapers in each city and leaving his mother and sister in charge each time he moved on. In 1768, Mary Katherine moved to Philadelphia with her mother. Two years later, Sarah died and William, who was in a fight with his financial partners, gave the Pennsylvania Chronicle to her. It was one of the largest printing shops in the colonies.

From 1771 – 1775, while William languished in debtor’s prison, Mary Katherine kept his businesses afloat. As he had done so many times before, in February 1774, William gave Mary Katherine control of the Maryland Journal, Baltimore’s first newspaper. William then concentrated his efforts on building a private postal service (one untouched by British rule that later became the U.S. Postal Service) and the masthead of the Maryland Journal was quietly changed to read “Published by M. K. Goddard.”

This was on the eve of the Revolution. By June 1774, most of the news on her front page was of Britain’s blockade of Boston Harbor. From then on, Mary Katherine’s paper became a tool of the Revolution, publishing Thomas Payne’s Common Sense in two parts, reporting on the first battles of the war and encouraging women to boycott British goods by growing their own flax and wool for clothing.

In July 1775, the Continental Congress approved William Goddard’s postal system and three months later named Mary Katherine Baltimore’s postmaster. This made her, in the words of the National Parks Service, “the first postmaster of Baltimore, the first female postmaster in the colonies, and eventually the first female postmaster in the United States.” According to the Smithsonian, it also “likely made her the United States’ only female employee when the nation was born in July 1776.”

Already familiar with her work and convened only blocks from her shop, Congress asked Mary Katherine to print the second version of the United States Declaration of Independence on Jan. 18, 1777, the first to bear the names of the signatories. At the bottom, it reads: “Baltimore, in Maryland; Printed by Mary Katherine Goddard.” According to the National Park Service, by using her full name instead of M.K. Goddard as she had on her newspapers, she “risked her life and her livelihood” in the event that the British government decided to charge her with treason.

Mary Katherine so excelled in her work that by 1779, the Maryland Journal had “as extensive a circulation as any newspaper in the United States.” Nonetheless, in 1784, William fired Mary Katherine from the Maryland Journal and took over as publisher. The reason is unknown, but it could have something to do with an incident years before when she refused to give up the name of a source for a controversial newspaper story and told the inquirers to talk to her brother, who was nearly banished from the United States because of it. Whatever the cause, the siblings never spoke again.

Mary Katherine remained Baltimore’s postmaster until October 1789 when newly appointed postmaster general Samuel Osgood replaced her with John White of Annapolis. The move was likely done for political reasons, as White was friends with Osgood, but most people took it as a sign of sexism. The official story was that because “supervision of nearby post offices was being added to the job description, more travelling might be necessary than a woman could undertake.”

The residents of Baltimore were outraged, with more than 200 demanding her reinstatement. Mary Katherine even wrote to George Washington and the Senate to try to get her job back. Washington refused to do anything and the Senate never responded, so Mary Katherine spent the rest of her life running a dry goods store and a bookstore.

When she died at the age of 78 in 1816, she freed her slave, Belinda Starling, “to recompense the faithful performance of duties to me,” and never having married or had children, left all of her worldly goods to her former slave.