Esunertos, or Iisuniirtos (fl. 50-30 BC), was a male ruler in Britain in the western Thames basin in the second half of the 1st century BC. He is known only from a few rare gold and silver coins, which provide the full spelling of his name – IISVNIIRTOS (II being a form of E favoured by early scribes in Britain at this time).^[1] This is also the first time that the Celtic nominative form -os- has been observed.^[2]

The name Esunertos has no parallel in contemporary histories for Britain, but is a recorded masculine name from the Roman period of occupation in Gaul. The name has been interpreted as 'mighty as Esos', a contemporary Celtic god.^{[3][lower-alpha 1]} It is not clear whether Esunertos was a friend or even usurper of Commius (or Commios). Nevertheless, alongside Commios, his is the earliest attested name on a British-made Iron Age coin.^[5]

Stylistically, the coinage is similar to Commios, ruler of the Atrebates. After Julius Caesar's invasion of Britain in 55 and 54 BC, he was made a client king at Silchester. Commios is known to have struck coins in his own name from 30 BC.^[6][7] The three known coins of Esunertos centre around Danebury Hill Fort, placing his territory around this prehistoric site towards the end of the Iron Age period.^[5]

In March 2023, Lewis Fudge, a metal detectorist unearthed a gold quarter stater coin in a field in the Test Valley of Hampshire.^[8][9] It was reported to numismatic experts at the Portable Antiquities Scheme and the Celtic Coin Index at the Ashmolean Museum. The reading was confirmed as [IIS]VNIRTOS, providing a new inscription in the British numismatic record.^[10] Prior to the Test Valley discovery, other coins had been incorrectly identified as unsigned issues of the Belgae tribe.^[10]

In September 2023, Spink confirmed that a coin of Esunertos would be sold at auction.^[5]

On 28 September 2023, Spink announced that this same coin had sold for £20,400 (including Buyer's Premium), setting a record for any Quarter-Stater ever sold at auction.^[3]