If you ever transported groceries from the store, or packed a lunch for work or school, chances are you’re familiar with Margaret Knight’s invention—the flat-bottomed paper bag. This was the most famous of several inventions that Knight patented at the end of the 19th century.

Margaret Eloise Knight was born on February 14th, 1838 in York, Maine. Her father died when she was young, which led the family to move to New Hampshire. Knight left school and began working in a cotton mill at only 12 years old in order to help her mother make ends meet. The cotton mill was a dangerous place for anyone in those days, especially a young girl, but it happens to be where Knight came up with her first invention. She saw other workers sustain injuries when using  some of the equipment, so she came up with a safety device that would protect workers from the hazardous conditions. Unfortunately, the pre-teen was not privy to the patenting process so she did not receive any compensation when her invention spread to other mills across the country.

In 1867, Knight moved to Springfield, Massachusetts and began working at the Columbia Paper Bag Company. Just like at the cotton mill, Knight observed problematic operations at the paper bag company and she sought ways to make improvements through invention. In 1868, she invented a machine that could quickly and efficiently fold and glue paper bags. The machine also gave the bags the iconic flat base that made packing items much easier. This time Knight knew she had to patent her invention, but she ran into trouble when Charles Annan, a man in the machine shop where Knight’s paper bag machine was being made, tried to steal the idea. Luckily, Knight had her original blueprints and was able to file a successful patent lawsuit, finally receiving a patent for her work in 1871. A model of Knight’s machine can be found in the Smithsonian’s National Museum of American History.

Knight went on to cofound her own paper bag company in Hartford, Connecticut called the Eastern Paper Bag Company. Before her death in 1914, she would patent over 25 inventions, ranging from machines for creating shoes, to a clasp for robes, to a window frame and sash. She is quoted as saying, “I’m only sorry I couldn’t have had as good a chance as a boy,” yet she was able to overcome many of the challenges and limits facing women inventors during her lifetime. Margaret E. Knight was inducted into the Inventors Hall of Fame in 2006.