The Claudian letters were developed by, and named after, the Roman Emperor Claudius (reigned 41–54). He introduced three new letters to the Latin alphabet: Ↄ or ↃϹ/X (antisigma) to replace BS and PS, much as X stood in for CS and GS. The shape of this letter is disputed, however, since no inscription bearing it has been found. Franz Bücheler identified it with the variant Roman numeral Ↄ, but 20th century philologists, working from copies of Priscian's books, believe it to instead resemble two linked Cs (Ↄ+Ϲ), which was a preexisting variant of Greek sigma, and easily mistaken for X by later writers...