John D. Morgan
The practice of renaming traditional Greek months, which almost always bore the names of annual festivals for the 12 gods or Dionysos or lesser divinities, after deified Macedonian rulers, took hold in the Seleucid Empire, with the months Seleukeios, Antiocheon, and Stratonikeon. Similarly, two years after Julius Caesar had reformed the irregular Roman calendar so that its years would closely correspond with solar years , the Roman month Quinctilis, on whose 12th day Caesar had been born, was renamed Iulius as part of his deification after he had been assassinated on the Ides of March of 44 BC (Suetonius, Divus Iulius 76; Cassius Dio 44.5; Censorinus 22; Macrobius, Saturnalia 1.12.34).
In 8 BC the proconsul Paullus Fabius Maximus suggested that the Greeks of Asia honor Augustus by replacing their traditional lunisolar calendar, which had ordinary years of 12 lunar months and intercalary years of 13 lunar months, with a Roman-style solar calendar, in which the year would begin on Augustus’ birthday on a.d. IX Kal. Octobres (September 23), which would be the first day of a month renamed Kaisar (Sherk, RDGE 65). In the same year (Censorinus 22), the traditional Roman month Sextilis was renamed Augustus. Suetonius (Divus Augustus 31.2), Cassius Dio (55.6.7), and Macrobius (Saturnalia 1.12.35) report that instead of September, in which Augustus had been born, Sextilis was chosen because in that month he had entered his first consulate and had won his most distinguished victories.
Papyri from the first century of our era attest many more examples of renaming the months of the Egyptian calendar after members of the Julio-Claudian imperial family.
In the previous cases the month which was renamed was one of the 12 usual months of a lunisolar or solar calendar. In contrast, several ephebic inscriptions with lists of months in various years (IG II2 2050, 2067, 2103, 2140; SEG XXVI 184) show that around 124 AD the Athenians honored Hadrian by renaming as Hadrianion not one of their usual 12 months in their lunisolar calendar, but the second Posideon, their 13th month in an intercalary year. Why they did so has not been explained previously.
SHA, Hadrian. 1.3, records Hadrian's birth “VIIII Kal. Feb. Vespasiano septies et Tito quinquies consulibus” (76 AD), and epigraphic evidence (CIL VI 33885; Inscriptiones Italiae XIII.2, 42 and 43) confirms that Hadrian’s birthday was VIIII Kal. Feb. = 24 January. As the 13th year of the 27th Metonic Cycle, the Athenian year 75/76 AD was intercalary: the year began July 2 with the first new moon after the summer solstice on June 24, and the first Posideon ran from November 27 to December 26, and the second Posideon from December 27 to January 24. Hence Hadrian was born on the last day of the Athenian intercalary month which would later be renamed Hadrianion. One may marvel at the sophistication of the ancient Athenians who calculated the date in their lunisolar calendar of Hadrian’s birthday almost half a century earlier.
Epigraphy and History