Inventions are often protected by patents. If you have a patent, it means you're the only one who can make, use or sell an invention. If other people use it, they have to give you money.

Patents stop people from stealing an inventor's ideas. Patents can be used for machines, food, medicines and other things. They can even be used to protect ideas.

Not everyone can get patents. Before the Civil War ended in the 1860s, most African-Americans were enslaved. They could not get patents.

This did not stop enslaved persons from inventing new things. Papan was an enslaved person who lived about 300 years ago. He made a new medicine for skin diseases. It worked so well that Virginia lawmakers freed him. They wanted him to work as a doctor and heal people.

Not all African-Americans were enslaved. Here are three African-American inventors who lived 300 years ago. They were all born free.

Benjamin Banneker

Benjamin Banneker was born in 1731. He taught himself math and became a mathematician. When he was 21, Banneker saw a pocket watch. He decided to build his own. A year later, Banneker invented a clock made of wood.

In 1792, Banneker wrote "Banneker's Almanac." Almanacs were books that said when the sun would rise and set. Banneker gave a copy to Thomas Jefferson. Jefferson was a Founding Father. Banneker asked Jefferson to stop slavery and give black men and women equal rights.

James Forten

James Forten was born in 1766. He served in the U.S. Navy and fought against Britain. Americans were ruled by the British at the time. In the Revolutionary War, Americans fought to be free.

After the war, Forten became a sailmaker. He created a tool to handle ship sails. He patented his invention and became rich. Forten used his money to support women's rights and to end slavery.

George Peake

George Peake was born in 1722. He fought in the Revolutionary War too. Peake lived in the town that later became the city of Cleveland, Ohio. He was the first African-American to live there.

Peake invented a mill for grinding corn. Peake didn't patent his invention.