Another previously unlocated Alexandrian XVIIIc has resurfaced at auction! It shares the same maker's mark that appears on the XVIIIc in the Royal Armouries: the letter P surmounted by a cross potent, twice repeated. It looks like this is the sword shown in the lower left in the photo from the Ottoman armoury, distinguished for the maker's mark and the damaged tip of the blade by Clive Thomas in his 2003 article. This one sold last month for the "low" price of only £200,000!
https://www.christies.com/lotfinder/...=6153918&lid=1