Sometimes throwaway remarks -- suggestions that seemed reasonable at the time -- are picked up by other writers, and what began as a good idea becomes a theory, and finally a fact.
This process has, I think, occurred in the case of the Britannia coins of the Roman empire. And I am grateful to a recent visitor (Fvrivs Rvfvs) for prompting this latest reflection of an old emperor, once again demonstrating the value of a blog in firing up new ways of thinking about old problems.
Hadrian's Provincial Coinage
To begin with the facts, it seems that the emperor Hadrian (r. AD 117-138) issued a series of "provincial" coins, celebrating his famous tours of the provinces. He certainly had cause to celebrate, for not one of his predecessors had managed to work his way around the entire empire, visiting each frontier in turn.
Here are the reverse "tails" sides from a few of the coins, showing (from left to right) Africa, Britain, Dacia, Germany, and Spain. Each province was personified by a deity, displaying some of the stereotypical attributes of the land. Thus, Africa wears the elephant-skin cap and, leaning against a basket of grain, reclines beside a lion.
Dacia, on the other hand, is seated on a pile of rocks, symbolising the mountainous terrain, and holds in one hand a standard and in the other the long, curved falx which was the characteristic weapon of the Dacians.
Germania, the scene of much Roman campaigning, is depicted as a proud warrior maiden, standing in defiant pose with spear and shield. And Hispania, another land of plenty like Africa, reclines holding an olive branch, while the rabbit motif at her feet symbolises fertility.
Britain, or Britannia, is a warrior maiden like Germany, with spear and shield, but her pose, like Dacia, is seated, indicating that, again like Dacia, she has been tamed by Rome, and her rocky seat is the stereotype of a mountainous province.
Frustratingly, none of Hadrian's coins can be dated accurately, but the Britannia coin (issued at some point during the years AD 119-127) is often said to date from AD 122 and to symbolise the commencement of Hadrian's Wall in that year. This standard interpretation probably began somewhere as "a good idea" and has become "a fact" which you will find in the standard books about Roman Britain and Hadrian's Wall.
Antoninus Pius and Britain
Having originated the personification of the various provinces under Hadrian, the Roman moneyers continued periodically to use the same characters whenever deemed appropriate. Thus, when Lollius Urbicus reconquered lowland Scotland for Antoninus Pius (your very own blogger, r. AD 138-161), coins were issued during the period AD 142-144 displaying Britannia on the reverse. The coin depicted below-left is an example of this.
However, coins issued during AD 155 (see above-center for an example) are usually said to depict a "dejected" Britannia, symbolising a disaster in the province. Perhaps the mauling of a legion, as Fvrivs Rvfvs seems to suggest. No doubt, this "dejection" theory began as somebody's good idea, but has now become a fact which you will find in the standard books about Roman Britain and the Antonine Wall. But the "sad" Britannia is really just a slight variation on the original personification found on Hadrian's coinage (pictured above-right).
Roman coins have been likened to the news agencies today. The reverse images carried topical messages around the empire. No doubt the depiction of a province like Britannia meant that something was going on there. But this old emperor would suggest that it was successes that were celebrated on coinage, and the "depressed" Britannia of AD 155 is really just the standard depiction of the deity. Of course, emotion is in the eye of the beholder ...