I posted about a year and a half ago that I thought the supposed image of Christ on the Hinton St. Mary mosaic looked more like the emperor Constantine, and last month got left a comment by Ciorst saying that archaeologists had been saying this for ages – Martin Henig said “this probably shows Christ, but a member of the family of Constantine, perhaps even Constantine himself who adopted the chi-rho as his emblem, remains an alternative possibility” in The Art of Roman Britain in 1995. It seems that sometimes when I get an idea in my head, I’m on the right track, so, despite the redoubtable Jona Lendering’s warning that “‘amateur historian’ is just another word for ‘unqualified’“, I’m going to have another go at it.
In AD 43, the Romans launched their conquest of Britain. The most common interpretation has been that they sailed from Boulogne and landed at Richborough in Kent (for example: Sheppard Frere, Britannia p. 48), but in recent years there has been some dispute about this. The only surviving account of the invasion is in Cassius Dio’s Roman History (book 60, Chs 19-23), and Dio says they sailed west. As you’ll see from the map below, Boulogne to Richborough is more-or-less north. So some (for example, John Manley in AD 43: a Reassessment) have suggested that perhaps they sailed from Boulogne to the Solent (the strait between the Isle of Wight and Southampton Water), which would be sailing west as Dio says. This theory has two added advantages as a theory: Dio says the invasion was launched in support of Verica, a deposed king who, based on his coin distribution, ruled in that part of the country, and Suetonius (Vespasian ch. 4) says the future emperor Vespasian conquered the Isle of Wight as part of the invasion campaign.
From Boulogne to Richborough and the Solent
However, there are good reasons for thinking that Richborough was the landing point. Frere says “Excavations at Richborough have revealed an early Claudian defensive beach-head perimeter which is clearly the scene of the main and possibly the only landing” (Britannia p. 48), and Dio’s account describes the Romans as fairly quickly advancing to a fording-point of the Thames “near where it empties into the ocean”, establishing camp there and sending word to Claudius. If, as it seems, the objective of the first phase of the campaign was to secure a strategic crossing-point of the Thames near its estuary, it doesn’t make much sense to sail west to the Solent, and then have to march so far back east.
So what’s the solution? Dio says the invasion fleet sailed in three divisions, so perhaps one landed at Richborough, another at the Solent, and the third somewhere else. But Dio also seems to describe a unified campaign from the landing to the Thames.
The key is to realise that the point of departure for the invasion fleet is not specified. Dio doesn’t mention it. Suetonius (Claudius 17) says that Claudius sailed to Britain from Gesoriacum (Boulogne), but Claudius and his reinforcements came later, in a separate sailing. It doesn’t necessarily follow that the main invasion force sailed from the same place.
Strabo (Geography 4.5.2), writing about 7 BC, says that in his time there were only four commonly used points of departure for Britain: the mouths of the rivers Rhine, Seine, Loire and Garonne. He also mentions Itium, another name for Boulogne,1 from which Julius Caesar sailed in 55 and 54 BC, although the implication is that it was no longer in common use. From the Loire and Garonne you would have to sail all the way around Britanny, probably to destinations in Cornwall. From the Seine, the most obvious destination is the Solent. From the Rhine, Strabo says it was usual to sail along the coast before crossing from somewhere between the territories of the Menapii and the Morini, two Belgic population groups. Richborough seems a likely destination, sailing west.
Routes to Britain according to Strabo
We know from Suetonius (Vespasian ch. 4 again) that the legion Vespasian commanded was transferred from a posting in Germania to take part in the invasion. According to L. J. F. Keppie’s Legions and Veterans: Roman Amy Papers 1971-2000 (p. 140) this legion, the II Augusta, was in Strasbourg, which is on the Rhine, and of the three other legions believed to have taken part, the XIV Gemina was in Mainz and the XX was in Xanten, both also on the Rhine. The fourth, the IX Hispana, was further south-east in Pannonia. It would seem sensible, if you wanted to gather these four legions in one place in preparation for a voyage to Britain, to do it via the Rhine.
I believe this theory is consistent with all the known facts and sources, but I haven’t seen it considered in print. Any and all more informed (and better qualified) comments welcome.
1 6 April 2010: Bill Thayer points out that Itium, aka Itius Portus, may not be Boulogne – see this page on his Lacus Curtius site and the linked articles. It may rather be Wissant, a little further north towards Calais.