Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
Federalist No. 54
They decided to use population as a determinant of votes in the House of Representatives, but the three fifths compromise that had taken place a year earlier before this paper was the event that sparked controversy between states, men, and political parties. James Madison, Hamilton's major collaborator, later President of the United States and "Father of the Constitution." He wrote 29 of the Federalist Papers, although Madison himself, and many others since then, asserted that he had written more. A known error in Hamilton's list is that he incorrectly ascribed No. 54 to John Jay, when in fact Jay wrote No. 64, has provided some evidence for Madison's suggestion. Nearly all of the statistical studies show that the disputed papers were written by Madison, but as the writers themselves released no complete list.