Eborius is only mentioned in history as among the three bishops from the Roman province of Britain attending the important Council of Arles in 314. That council was convoked by Constantine the Great with the special object of deciding the question of Cæcilianus and the Donatists. Among the bishops from ‘the Gauls’ present at the council was ‘Eborius episcopus de civitate Eboracensi, provincia Britanniæ.’ His British colleagues who are mentioned after him were ‘Restitutus, episcopus de civitate Londinensi’ and ‘Adelfius episcopus de civitate colonia Londinensium,’ the latter name being conjecturally emended into ‘Legionensium,’ i.e. Caerleon-on-Usk. ‘Sacerdos presbyter’ and ‘Arminius diaconus’ also attended the council with the three bishops. The mention of their names is the most definite piece of evidence of the existence of an organised Christian church in the Roman province of Britain, and of its close dependence on the church of Gaul. It is worth noting that among the canons they subscribed was one fixing a single day for the celebration of Easter throughout the world. So that the different custom of the British church on that question had not yet arisen. The above facts are in Labbe's ‘Concilia’ from a Corvey MS., and Isidorus Mercator's list substantially agrees in including ‘Eburius,’ though it describes him only as ‘ex provincia Britanniæ’. The passage is wrongly punctuated in Migne's edition; but in Crabbe the reading is ‘ex provincia Bizacena, civitate Tubernicensi, Eburius episcopus.’ Tillemont conjecturally identifies Eborius with the Hibernius who joins in a synodal letter to Pope Sylvester I, but this seems quite arbitrary. The similarity of name, ‘Eborius’ and ‘Eboracum,’ is perhaps a trifle suspicious; but Ivor, easily Latinised into ‘Eborius,’ was a common Welsh name.