Was the husband of the most famous of Celtic British women, Boudicca. He was made client of Rome and given kingship over the entire Icenian tribe following the Icenian War in AD47, when the inter-tribal struggles between Anted[ios], who had been recognised by Rome, and the factions of Aesu[...] and Saenu[...], escalated into armed revolt against Rome, which was soundly crushed. One unique issue of his coins bears the inscription SUB RI PRASTO ESICO FECIT - 'under king Prasto, Esico made me', which not only gives us the name of the king but also his moneyer or chamberlain. His death c. AD60 was to spark the rebellion led by his wife, Boudicca, which was to end with the complete subjugation of the Iceni.
http://www.roman-britain.org/tribes/iceni.htm