BITHYNIA. Nicaea. Commodus, 177-192. Diassarion (Bronze, 25 mm, 9.42 g, 7 h). Α Κ Μ ΑY ΚΟ ΑΝΤΩΝЄΙΝOϹ Bare-headed, draped and cuirassed bust of Commodus to right, seen from behind. Rev. ΙΠΠAPXOC NIKAIЄΩN Hipparchus the astronomer seated left, pointing with his right hand on globe set on column and leaning left on seat. RPC IV.1 online 5545 var. (Hipparchus resting his right hand on knees, globe set on broader column in the back). Of the highest rarity, the fourth known example and the first of this variety. Fine.

Hipparchus of Nicaea (circa 190-120 BC) was the most famous astronomer of his time. He calculated the duration of a solar year with inconceivable precision (he was off by just 6 minutes and 30 seconds based on modern precision measurements), mapped the positions of some 900 stars, invented a method to calculate the longitude and latitude of locations on Earth, and is also considered to be the founder of modern trigonometry. Having died on Rhodes in circa 120 BC, he was praised as one of the most famous citizens of his native city of Nicaea in Roman times, worthy to be commemorated with a series of coins that show him on the reverse with a globe - an attribute singularly appropriate for a famous astronomer