
Near the buttonwood's accord lies a field of Christ. His marker there would make even Khafra smile.
The solution to the fundamental elements of this clue was announced on Dan Brown's Facebook fan page by Cheryl Lynn Helm, about 30 minutes after the clue was posted. Good for you, Cheryl!
"Buttonwood's accord" is a reference to the Buttonwood Agreement of May 17, 1792, which established the New York Stock & Exchange Board (later known as the New York Stock Exchange, now the NYSE Group). The agreement was signed by 24 stockbrokers under a buttonwood (i.e., sycamore) tree outside 68 Wall Street in lower Manhattan, New York City. Of course, the New York Stock Exchange was and remains fundamental to the development of American-style capitalism.
"Field of Christ" is a reference to a cemetery. U.S. Founding Father, Alexander Hamilton, is buried in the Trinity Churchyard Cemetery, perhaps a 5-minute walk or so from the location of the Buttonwood Agreement. His grave marker (the "marker" of the clue, of course, shown above) is in the form of a pyramid with a flat apex.
The Next Level
Warning: no matter how weird things get in this section of the post, I want you to remember: everything in "The Next Level" actually happened in real life.
Alexander Hamilton (b. 1755 or 1757--d. 1804) is on everyone's list of U.S. Founding Fathers. Like many of them, he was a Freemason. He was the first U.S. Secretary of the Treasury, and as such ties into the financial theme that runs through this clue. However, it gets murkier than that, and intensely conspiratorial, in real life, very quickly.
Hamilton was mortally wounded by Aaron Burr, in a duel in Weehawken, NJ, just across the river from Manhattan Island. At the time, Burr was serving as the Vice-President of the United States, under Thomas Jefferson in Jefferson's first term as President. Burr came under intense criticism, especially among Northern voters, for killing Hamilton. Burr left the Vice Presidency at the end of his term (Jefferson entering a second term as President with a different VP), and then things really got weird.
Burr moved into what was then the West of the territories of the U.S., and apparently came up with a scheme that, if successful, would have left him as essentially the king of a separate nation, incorporating much of what is now Texas, northern Mexico, and nearby areas. (I should point out that these were the very areas later focused on by the Knights of the Golden Circle, or KGC, whom we met in Clue #34; see this article with its provocative map).
Burr was arrested and put on trial for treason, but was acquitted for lack of evidence. The team for the prosecution included the young William Wirt, whom we met in Clue #6. (You will recall Wirt as the Freemason who later abandoned the Masons, and ran against Jackson for the Presidency on the Anti-Masonic Party ticket; after his death, Wirt's corpse was beheaded, and his skull was stolen right out of his crypt in the Congressional Cemetery.)
(Incidentally, Burr was not a Mason. However, his defense attorney, the young Henry Clay -- distant relative of my wife, Kathleen -- was a very prominent Mason later in his life.)
Which leaves us with Khafra. I find it interesting that the alternate spelling of his name, Khafre, is also the name of a sophisticated block cipher developed 20 years ago. The publication of the cipher was originally blocked by the National Security Agency, but through a variety of mishaps it came to public attention anyway.
So there we have it: Founding Fathers, a fatal duel, a conspiracy to rule a chunk of North America, pyramids galore, and a code scheme so threatening that the NSA wanted to block its publication -- and all in real life. What's not for Dan Brown to love?
Potential Relevance to The Lost Symbol
You can't have a good conspiracy without a hefty amount of cash. The clue points in passing at one of the most massive wealth-engines in human history, the New York Stock Exchange, founded in the earliest days of the American Republic -- hey, Washington was still in his first term. Perhaps the conspiracy that Dan Brown depicts in his novel has something to do with the NYSE. (Of course, the Confederate gold mentioned in Clue #34 might work in here, too.)
My guess is that, in the novel, Burr somehow has connections with the KGC, connections that somehow reverberate down to our own day. (Thus, the KGC would be the "bad guy" secret society in the novel. Would the Freemasons be the "good guys"?)
In the world of the novel, Hamilton's flat-topped pyramid may resonate with the unfinished pyramid of the Great Seal of the U.S., discussed in relation to Clue #35.
The Khafre cipher can encrypt small amounts of data very quickly, which, in Dan Brown's universe, could come in mighty handy . . .