Recent developments in Unicode have made it possible for a large variety of historic characters of the Slavic languages to be correctly encoded in Unicode. However, there are some areas which require additional work, and for other problems, several solutions co-exist. A puzzling problem arises when texts contains obvious errors, especially so if one single text is the only available source for the claimed existence of a specific letter. The Glagolitic "Pe" character is such a character, and because it represents such a unique case, it paper will present a fresh look at the original source (the famous "Munich Abedarium") and its interpretation.