Did you know Mississippi didn’t officially abolish slavery until 2013?

Two medical colleagues from Mississippi once noticed a historical oversight after watching a film about the final moves by U.S. President Abraham Lincoln to secure the 13^th amendment that will abolish slavery.

Until February 7, 2013, that oversight was never corrected.

Essentially, the state of Mississippi had until that date not officially abolished slavery because it had never submitted the required documentation to ratify the 13^th amendment.

The 13th amendment, which outlawed all slavery and involuntary servitude except as a punishment for a crime, was passed by the U.S. Senate on April 8, 1864, and by the House of Representatives on January 31, 1865.

That same year, 26 states ratified the law and in December of that year, the amendment was officially adopted into U.S. law after Georgia gave its approval, bringing the number to the required 27.

Scores of states waited years to ratify the amendment, with the last being Mississippi in 1995, but because the state never presented the ratification document to the U.S. archivist, it was never considered official.

Almost everyone had overlooked this clerical error until the movie that inspired Dr. Ranjan Batra, professor of Neurobiology and Anatomical Sciences at the University of Mississippi Medical Center, to look into the matter.

After watching Steven Spielberg’s Oscar-nominated film ‘Lincoln’, which focuses on the passage of the 13th amendment, Batra, who is an immigrant from India, knew that he needed to take action.

“At the end of the story there was an open question about how the ratification process proceeded,” he told ABC News. “Living in the South as I do, I found that a pretty big open question.”

Batra began his own investigations and subsequently noticed on the website usconstitution.net that there was an asterisk next to the state of Mississippi concerning the ratification of the 13^th amendment.

“Mississippi ratified the amendment in 1995, but because the state never officially notified the US Archivist, the ratification is not official,” the statement on the website read.

Inspired further to resolve this oversight, Batra contacted his University of Mississippi Medical Center colleague Ken Sullivan, who was ready to help.

One of the first actions Sullivan took was to call the National Archives Office of the Federal Register, which confirmed that Mississippi had indeed not yet ratified the law.

The longtime resident of Mississippi then took a trip to the state archives to acquire a copy of the bill.

“The last paragraph [of the bill] directs the Secretary of State of Mississippi to inform the national archives of the law of the ratification which is exactly the way ratification is supposed to proceed, but that hadn’t been done for whatever reason,” said Batra.

Sullivan later watched ‘Lincoln’ with his family. There and then, he was moved further to help correct the error.

Sullivan contacted the office of Mississippi Secretary of State Delbert Hosemann, who agreed to file the required documentation to the National Archives and make the ratification official. On January 30, 2013, Hosemann sent the necessary paperwork to the Office of the Federal Register.

A week after, on February 7, 2013, Mississippi received word from the Office of the Federal Register that confirmed it had officially ratified the Thirteenth Amendment.

“We finally got it right,” said Senator Frazier, who helped develop the bill.

Sullivan, Batra and many others were, of course, elated that the error was fixed, considering Mississippi’s history with slavery.

In 1820, Mississippi had 33,000 slaves, and this number ballooned to about 437,00 after forty years, giving the state the country’s largest slave population, according to a report by Mississippi Encyclopedia.

New births did contribute to that astronomical figure, nevertheless, slave trade became a crucial part of Mississippians’ social and economic life, the report added.

“Few, if any, southern States received as many slaves and exported as few,” historian Charles S. Sydnor wrote.