This study resolves a two-millennium-old cartographic puzzle by applying geodetic reverse resection from major Mediterranean stations to redefine Claudius Ptolemy’s Prime Meridian ($0^\circ$). The mathematical and error-theory analysis demonstrates with 95% confidence that the ancient "Fortunate Islands" are uniquely identified with the Azores archipelago, rather than the Canaries or Cape Verde. Furthermore, the investigation decodes the Tropic of Cancer as the actual latitude Datum used during the summer solstice, vindicating Ptolemy’s scientific accuracy and revealing an advanced, lost timeline of ancient Atlantic navigation.