Illinois state historians on Tuesday confirmed that the handwriting found on a book called "Types of Mankind" belongs to none other than Abraham Lincoln, Time reported.

Employees at the public library in Clinton, Illinois had long believed that Lincoln had written in the book, which offers theories that different races were created at different times and therefore cannot possibly be equal.

Experts say that on an early page in the 700-page work, Lincoln wrote the name Clifton Moore in the margins, indicating who owned the book. A lawyer later wrote a note below Lincoln's saying that it was, in fact, Lincoln who wrote the original note.

Upon studying the handwriting, historians found that it was a perfect match with other documents that are known to be written by the 16th president of the U.S.

"There are certain letters of the alphabet that Lincoln wrote in a way that were not common to his era," said the curator of Lincoln's presidential museum James Cornelius. "A forger can typically do some of the letters in a good Lincolnian way. They'll give themselves away on a couple of the others. This all adds up."

The curators of the museum went out of their way to make clear that they don't think Lincoln agreed with the beliefs presented in "Types of Mankind," even if he did read the text.

The authors of the book wrote that Africans and Native Americans were fundamentally different from Caucasians, and enslaving them was part of the natural order, according to Fox News. Slave owners often subscribed to these beliefs as it diminished their remorse for their livelihoods.

"Everything we know about Lincoln's legal, religious and scientific thinking tells us he rejected that argument," Cornelius said, adding that as a presidential hopeful, Lincoln likely was educating himself on opposing arguments on matters of race.