), in Gallia, a river which is a branch of the Sequana (Seine
), Autesiodurum or Autessiodurum (Auxerre
) is on the Yonne.
The name Icaunus is only known from inscriptions. D'Anville (Notice, &c., s. v.
Icauna) states, on the authority of the Abbé le Beuf, that there was found on a stone on the modern wall of Auxerre
the inscription DEAR ICAVSI. He supposes that Icauni ought to be Icauniae, but without any good reason.
He also adds that the name Icauna appears in a writing of the fifth century.
According to Ukert (Gallien,
p. 145), who also cites Le Beuf, the inscription is “Deabus Icauni.” It is said that in the ninth century Auxerre
was named Icauna, Hionna, Junia. (Millin, Voyage, i.
p. 167, cited by Ukert, Gallien,
p. 474.) Icauna is as likely to be the Roman form of the original Celtic name as Icaunus.