Ptolemyʾs Geographike Hyphegesis (Introduction to Geography) (ca. AD 150) consists of a huge and invaluable stock of topographical information. More than 6,000 toponyms are even defined by coordinates. Nevertheless, Ptolemyʾs cities are often misplaced or pop up more than once in his maps. This is especially true with his confusing description of Armenia (geogr. 5.13), which caused a modern scholar to call it a ‘parody’ of his work and method. This paper aims at clarifying the basic error in all of Ptolemyʾs coordinates and proposes some explanations and corrections for his Armenian toponyms.