Who is this person?

[RJNorton]

Gene, is the right answer a person whose been previously mentioned on the forum?

[J. Beckert]

Daniel Webster is ringing a bell.

[Gene C]

This person has been mentioned before, but it's not Daniel Webster

[Steve]

Alexander Stephens.

[AussieMick]

Henry Clay?

[Gene C]

Steve got it right. Congratulations!
I hadn't even started the more informative clues yet.

My source is "Lincoln in Private" by Ronald White

Your prize is the esteem of your fellow members of the forum, and to advance to the next round of trivia here on the Lincoln Symposium.

[Gene C]

Abraham Lincoln is buried at a large tomb in Springfield, Illinois. Mary Lincoln, and three of their four sons are buried there.
Over the years there have been many repairs, renovations and updates made to his tomb.
Yet, there is one more person who was buried here. Who is it?

[RJNorton]

James Matheny?

[Gene C]

James Matheny is buried in the same cemetery as Abraham Lincoln (Oak Ridge) according to Find A Grave, but he is not interred in Lincoln's tomb.

Also according to Find A Grave - His (Matheny's) popularity was unequaled & his funeral was said to have been the largest in Springfield since that of Abraham Lincoln.