The original post and ensuing discussion had to do with the American Revolution, so I figured Founding Fathers Artifact. There's also the fact that in W13 canon, historical accuracy isn't always what it appears to be on first blush. (Oddly, in terms of ones that were mentioned in canon, the Founding Fathers are pretty thin on the ground. Of the three on the wiki, considering George Washington's teeth gave me no properties to work with, the lightning rod seemed to be the best one.)

The Artifact of my heart for this would be the original copy of the Declaration, but that's purely headcanon.