France donates a new statue of liberty to the United States. In honor of that, I can publish a chain of reasoning that I have already rejected.
Clue 5 combined score 1-10 and ended up in Angers. Clue 6 started in Angers. Angers has a 6th Engineer Regiment. Preneste fibula means the beginning of letters and this leads to instruction and engineering skills. Al-mar means the Marines we find in Poitiers. Poitiers also has a chemical industry. Charles Martel won Maures in Poitiers, so the title could mean that too.
Poitiers has a copy of the Statue of Liberty. If we think the statue is a clef, then we find a ship: Isere, who carried the statue to New York. Isere’s home port was Lorient. We can see that Lorient and Angers and Bourges are on the same line and if we continue the line, we will also find Louhans.
However, we can think that freedom is the key (clef) and the statue is the ship that carries freedom. The statue was originally brown, almost black.
If we now draw a line from Poitiers through Bourges to Colmar, Barthold’s hometown, we will find another copy of the Statue of Liberty. Twice, ‘Freedom Enlightening the World’. Darkness will shine.
There are several possible Sentinels in Colmar. However, they are a little west of the Statue of Liberty.
I myself abandoned this road, but you can continue here if you wish.