A giant gilded statue of a Roman emperor once stood proudly in the heart of the Scottish Borders, new research suggests.
It had previously been assumed that a bronze leg found in a bog in Milsington near Hawick in 1820 was loot taken from a site further south - possibly York.
However, experts now believe it came from a sculpture of Antoninus Pius on horseback - similar to the one of his successor Marcus Aurelius in Rome - and was erected to mark the conquest of southern Scotland.
Dr Fraser Hunter, principal curator of prehistoric and Roman archaeology at National Museums Scotland (NMS), said: "This really turns on its head our understanding of Rome's second attempt at conquering Scotland."
The sculpture is the only known example of its kind from Scotland and has been reconstructed using its surviving leg ahead of a major new exhibition opening at NMS in Edinburgh this weekend.
The larger than life-sized lower leg with a boot dates back to about 140 AD and is one of the most striking treasures from Roman Britain in the NMS collection.
A wider study of statue fragments from the Roman frontier showed that bronze imperial statues - including equestrian ones - were erected in frontier forts, thus making a Scottish location for this particular statue more feasible.
In addition, researchers said the way the leg was removed suggested the deliberate Roman dismantling of a valued sculpture as they withdrew from southern Scotland, rather than a local act of revenge.
They said it had been carefully removed, not "brutally hacked off".
Examination of the top of the leg has found that there are no cut marks, but rather it remains exactly as it was cast.
The absence of gilding around the knee shows that this area was covered by a tunic or cloak, with lumps around the top which in-filled the folds of the tunic and stuck the leg to it.
This contrasts with examples of statues being deliberately destroyed after a battle, when an emperor's memory was condemned, or when they were chopped up for scrap, typically resulting in irregular fragments on a much smaller scale.
Such careful removal and burial has been found widely in Roman Scotland when the Antonine conquests were abandoned, such as the careful burial of Antonine Wall inscriptions and of the Inveresk Mithras altars, which are also on display in the exhibition.
Once curators had established that the statue was likely to have been erected in Scotland, they looked to answer the question of who it depicted.
They came to the conclusion that just one emperor paid particular heed to his Scottish victories - Antoninus Pius.
His conquest of what is now southern Scotland was the only foreign adventure that he commemorated with the title Imperator, a battle-honour meaning "commander" which marked an emperor's victory.
Hunter said: "This was a big deal for the emperor, something which was worth celebrating.
"It offers us a tantalising glimpse into the kind of grand monuments which once stood in southern Scotland and shows the importance Pius placed on his victories in Scotland.
"But it begs the question - where is the rest of the statue?".
Roman Scotland: Life on the Edge of Empire is at NMS in Edinburgh from 14 November to 18 April.
Who was Antoninus Pius?
Antoninus Pius was Roman emperor for more than two decades, from AD 138 to 161.
He has been described as "mild-mannered and capable" and was the fourth of the "five good emperors" who guided the empire through an 84-year period of "internal peace and prosperity".
He succeeded Hadrian and it was during his reign that a 36-mile (58km) garrisoned barrier - the Antonine Wall - was built to extend the Roman frontier 100 miles (160km) north of Hadrian's Wall.
After his death, the empire suffered invasion by hostile tribes and civil unrest.