EGYPT, Alexandria. Antoninus Pius. AD 138-161. BI Tetradrachm (23mm, 11.83 g, 12h). Dated RY 6 (AD 142/143). Laureate head right / Phoenix standing right; AI ωN above, L ς (date) across field. Köln 1424-5; Dattari (Savio) 2431; K&G 35.180; Emmett 1419.6. Toned, roughness. VF.
From the Stein A. Evensen Collection. Ex Classical Numismatic Group Electronic Auction 216 (12 August 2009), lot 416 (hammer $270).
AD 139 marked the renewal of the Great Sothic Cycle, a cycle of 1461 years beginning when the star Sothis (Sirius) rises on the same point on the horizon as the sun. This tetradrachm type was initially minted in year 2 (AD 138/139), but was reintroduced again for year 6 of Pius' reign.