The Crown of the Crusader Kings

The Crown of the Crusader Kings is a Scrooge McDuck comic by Don Rosa.

Plot
To make up for the loss of the Crown of Genghis Khan, Scrooge McDuck and his nephews looks for its Western equivalent, the Crusader Kings' crown, sent to Cathay on Cristoforo Colombo's expedition in 1492 and still hidden in the Caribbean.

To locate it, they first recover Colombo's logbook in a hut in the Arctic, left there by explorer Adolf Erik Nordenskiöld, and read that "the templar hid the crown". They visit the International Money Council (already mentioned in the Carl Barks' comic The Fabulous Philosopher's Stone) in Paris looking for additional clues, and Director Molay reveals to them that the Knight Templars, a crusader order which evolved into Europe's first bank network, ceded to the Kings of Spain and Portugal the crown to be sent to Cathay, in exchange of a share of the future trade, with the proviso that, should the voyage fail to reach its destination, the contract would become null and void by October 13, 1582, and the crown would be returned to the Order; it's also mentioned that the Templars, whose properties were seized by Philip IV of France, managed to spirit away their treasury in several locations, including Scotland.

Molay accompanies the Ducks to Haiti, but purposefully attempts to send them on a wild goose chase; when they nevertheless manage to locate the crown, he claims ownership of it, as the IMC was formerly the Bank of the Templar Order. The Ducks manage to prove that his claim is null and void because of the switch to the Gregorian calendar (executed by skipping ten days), which meant that there never was an October 13, 1582. Eventually, however, the government of Haiti is recognised as the rightful owner of the crown, and Scrooge is satisfied by keeping the fabric on which the crown was wrapped in as it is the Clan McDuck tartan, indicating the Knights Templar's vast treasure is located at castle McDuck.

The story continues in ''The Old Castle's Other Secret or A Letter From Home.