The Venerable Bede tells us that King Lucius converted to Christianity in around 180AD. He says that the King asked Pope Eleutherius to send teachers to instruct him. Bede got this from Liber Pontificalis of c 590. There is also a tradition that St Peter’s Cornhill in London was set up by King Lucius.
Bede is considered to be a reliable historian but the tradition has been written off as a legend. Indeed there are questions to be answered, but it is more than a legend and perhaps less than an established fact.
Not the least of the questions to ask is: ‘ what does it mean to be King in the context of Roman occupation?’ But of course, you could ask the same question of King Togidubnus who is called Great King of Britain in a Roman Temple inscription in Chichester.
As to the early origin of St Peters archaeologists have mostly written off the tradition as St Peter’s is built over the Roman Forum and so how can it have been the site of a Christian Church at this early time?
But the position of St Peter’s right on the centre of the Forum’s Basilica is intriguing. This is where a municipal shrine room was likely to be. The East wall of the Church is only 2 degrees out of alignment with the Forum (although the rest is more skew-wiff.) And the clincher is that recent archaeology shows that the Basilica of the Forum was pulled down in about 300AD. So there is a real possibility that this was the site of Britain’s Roman period Cathedral. We know London sent at least one Bishop to Constantine the Great’s Council of Arles in 314AD so a Christian community in London must have predated this time. There is a fainter possibility that the shrine room was converted for Christian use in Lucius’ time.
Where does that leave King Lucius? There are well attested Christian traditions that Britain was an early convert to Christianity. (See my book ‘In Their Own Words – A Literary Companion To The Origins Of London‘ D A Horizons, 2009. Kevin Flude and available here. Extract below) It has been suggested that Lucius of Britain was confused with Lucius of Edessa but this is not very convincing. The possibility is that someone, either descended perhaps from Togidubnus, or a King from an area of Britain not under direct Roman control (Silures? Brigantes?) converted to Christianity in the time of Pope Eleutherius.
For further reading, see ‘King Lucius of Britain by David J Knight.
King Lucius may not be a saint, but he has a feast day because of his connections to Chur in Switzerland which saw him enter the Roman Martyrology. Knight suggests that the tradition of the martyrdom of Lucius in Chur comes from the transplanting of rebellious Brigantes to the Raetia frontier in the 2nd Century AD bringing with them the story of Lucius and that possibly at the end of the King’s life he travelled to join the exiles in Switzerland where he met his unknown end.