Hadrian’s Wall is impressive, even in decline. A massive stone boundary striding across today’s landscape, its very size sends out messages: ‘It was intended as a defensive line’; ‘It was built to impress’; ‘It marked the edge of Caesar’s land’. These are all matters that we continue to probe today. We also argue about the date that the army started to build it, and how long it took them. On this subject, we have little to go on. A statement in ancient literature penned over two centuries after the event attests that Hadrian came to Britain and was the first to build a wall 80 miles long to separate the Romans and ‘barbarians’. A handful of inscriptions and the evidence offered by archaeological investigations offer further clues. Yet we in Britain are lucky: this is quite a lot of evidence compared to other frontiers.
We can work out that it was in AD 122 that Hadrian visited Britain, and building inscriptions associated with the Wall bear his name. Nevertheless, we have nothing that tells us when the monumental task of building was completed. No ancient author states ‘this was the year that Hadrian’s Great Wall was finished’, or words to that effect. No inscription has been found recording that it was the last stone to be laid on the Wall. In order to seek an answer to the question, ‘Was Hadrian’s Wall finished by the death of the emperor in AD 138?’ we have to turn to archaeology.
In 1986, to his great surprise, Jim Crow found an extra tower on Hadrian’s Wall. The turrets along the Wall – in reality towers, but named after the Latin turres – were regularly spaced, but between turrets 39a and 39b, close to the centre of the Wall, there sat an extra tower. Its history proved to be equally interesting: it was not an original part of the blueprint for the Wall, but butted against it – the Wall itself had been built in two phases, with a significant gap between them. After the foundations had been laid, it seems, building work paused long enough for a layer of peat 600mm (2ft) deep to develop at the place where the tower was to be erected. Further indication of a lengthy hiatus was that a bonfire large enough for its ashes to spread on both sides of the Wall had been lit, which suggests that a considerable amount of scrub had grown over the abandoned foundations.
