EGYPT. Alexandria. Antoninus Pius, 138-161.
Drachm (Bronze, 34 mm, 21.20 g, 11 h), RY 8 = 144/5. ΑΥΤ Κ Τ ΑΙΛ ΑΔΡ•ΑΝΤ[ⲰΝΙΝΟϹ CЄΒ] ЄΥC Laureate head of Antoninus Pius to right. Rev.
[L] - H Ram (Aries) leaping right, head to left; to upper left, helmeted and cuirassed bust of Ares (Mars) to right; above, star. Dattari (Savio) 2958. Emmett 1461.8. K&G 35.267. RPC IV.4 online 13540. Very rare. Light doubling, otherwise,
about very fine.From the Rhakotis Collection, formed in the 1960s and 1970s (with collector’s ticket).
In year 8 of Antoninus Pius’ reign, a remarkable series of bronze drachms was struck in Egypt showing the twelve signs of the Zodiac, each accompanied by one of the five planets known in Antiquity (Mercury, Venus, Mars, Jupiter and Saturn), the Sun or the Moon (also considered to be planets by the ancients). The pairings followed astrological theory, which dictated that each planet ruled over a so-called day and night house, with the luminaries each ruling a single house according to their diurnal or nocturnal nature. Thus, we see Venus in her night house of Taurus and her day house of Libra, the Sun in his day house of Leo, Jupiter in his day house of Sagittarius, and so on. Whenever a planet entered its respective house(s), its effects on human affairs would be enhanced.
For a long time, it has been assumed that the Zodiac coins were connected with the completion of a Sothic cycle in 139 CE. Originally, the Egyptian civil calendar had its beginning on the day of the heliacal rising of Sirius in July, shortly before the start of the Nile inundation. However, the Egyptian civil calendar only lasted 365 days, whereas there are 365.25 days between two successive heliacal risings of Sirius. In other words, every four years, the civil calendar shifted by one day versus the “Sothic year” (Sirius is called Sothis in Greek). After 1460 Sothic years, or 1461 civil years, the heliacal rising of Sirius again took place on the first day of the month Thoth (Egyptian New Year), and a Sothic cycle was completed.
While this was certainly a momentous occasion, N. Vaneerdewegh ('The Egyptian "Zodiac Coins" of Antoninus Pius and the Sothic Cycle' in F. Stroobants & C. Lauwers (eds.), Detur dignissimo: Studies in Honour of Johan van Heesch, 2020, p 315-325) convincingly argues that the link between the Zodiac coins and the Sothic cycle is tenuous at best. There are no explicit references to Sirius in any of the types, and the coins were struck in 144/5 CE, several years after the completion of the Sothic cycle. Year 8 of Antoninus Pius also saw the output of a series of nome coins in Egypt, and these were connected by A. Geissen (‘The Nome Coins of Roman Egypt’, in C. Howgego, V. Heuchert & A. Burnett (eds.), Coinage and Identity in the Roman Provinces, Oxford, 2005, p. 167-170) to the marriage of Marcus Aurelius and Faustina the Younger in 145 CE. The Zodiac coins may likewise be connected to this marriage, which provided the empire with a secure succession, and thus promised the dawn of a new golden age, blessed by the heavens.