excellent photography!..the TINC/Horse GOLD STATER is a very rare Celtic Gold Stater of the Regini tribe who were closely allied with the Artrebates. This coin is named for the king Tincomarus who was a son of Commios. It is listed as ABC 1061 in the ABC book by Chris Rudd and dated approx 25 BC - AD 10
He was an early friendly king to the Roman invaders of England
in fact most of the gold for the celtic coins came from the Romans as there was little to be found on the island.