Sunday, December 6, 2015 marks one of the most important dates in U.S. History. 150 years ago, the Thirteenth Amendment to the Constitution, outlawing slavery in all forms, received the required votes for passage. What many Americans may not know, however, is that the amendment itself was penned by a Missouri senator.

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Missouri U.S. Senator John Brooks Henderson of Louisiana wrote and introduced the historic amendment. Henderson was a Pike County Missouri lawyer and veteran of the Civil War. He came to the realization that political debate and public conflict over the issue of slavery would only continue until it could be solved legally.

And that was what he set out to do.

The passage of the Thirteenth Amendment came as a significant event, not only because it meant freedom for African Americans, over half of the U.S. population, but also because it marked the first time in sixty years that the Constitution had been altered in any way. It was also the first time that the U.S.'s founding document prohibited any action by individuals instead of by the government.

Though Senator John Brooks Henderson goes largely forgotten by today's history books, he played a critical role in changing the course of U.S. history. Henderson also played a critical role in the passage of the Fourteenth and Fifteenth Amendments, fought for voting rights for women, dealt in affairs with Native Americans, and prosecuted federal tax cheats. If not for this Missouri man from Louisiana acting against slavery, there's no knowing where America would be 150 years after.