Tasciovanus is known only through numismatic evidence. He appears to have become king of the Catuvellauni about 20 BC, ruling initially from Verulamium (St Albans). For a brief period ca. 15-10 BC his coins were issued from Camulodunum (Colchester), so it would seem he ruled over the Trinovantes at this time. After this his coins were once more issued from Verulamium, and no longer refer to him by the Latin title of "rex" (king). He reconquered Camulodunum by about 9 AD, and died not long afterwards.
He had two notable sons: Cunobelinus, who succeeded him, and Epaticcus, who gained territory at the expense of the Atrebates.
A Genealogy preserved in the medieval Welsh manuscript Harleian 3859 contains three generations which read "Caratauc map Cinbelin map Teuhant". This is the equivalent of "Caratacus, son of Cunobelinus, son of Tasciovanus", putting the three historical figures in the correct order, although the wrong historical context, the degree of linguistic change suggesting a long period of oral transmission. The remainder of the genealogy contains the names of a sequence of Roman emperors, and two Welsh mythological figures, Guidgen (Gwydion) and Lou (Llew).
| Preceded by: Cassivellaunus | King of the Catuvellauni | Succeeded by:<br.>Cunobelinus |