Home from Rome: there has long been a bond between Scotland and Italy, a new exhibition shows just how far back those links run

• Artists such as Nicola Benedetti are living proof of the bond between Italy and Scotland

"We're talking about a significant relationship that exists over 2,000 years," says Gabriele Papadia de Bottini, Scotland's Italian consul-general and acting director of the Italian Cultural Institute. He coordinated the exhibition to coincide with the Pope's visit this week. "The idea was to celebrate the link by bringing together material that came only from Scotland. That in itself is significant. We didn't need to bring items from outside. There is so much evidence of the connection here - in the museums and the cityscapes, in the Scots-Italian community and the gastronomy."

Still, it has been thought that the Roman influence on Scottish culture wasn't as strong as it was south of the Border. Indeed, a Wikipedia entry baldly states that it hasn't endured. Scotland and Rome - Centuries of Enrichment aims to prove otherwise.

Many of the pieces in the exhibition come from Glasgow's Hunterian Museum, which boasts the biggest Roman collection in the country. The other contributors are the National Galleries of Scotland, National Library of Scotland, Faculty of Advocates, Scottish Catholic Archives, and the RSA. It reveals a thread between two nations that cuts across art, culture, law, religion and history itself. From 2,000-year-old pieces of pottery to the 15,000 Italians registered with the Italian consulate, Scots and Italians go together like, well, haggis on a pizza. "And there are a further 30,000 people of Italian origin in Scotland," explains Papadia over coffee at the Italian Consulate in Edinburgh's New Town.

"This is a community who first came to Scotland from Italy in the 19th century and are now so integrated they are Scots-Italians.Sharleen Spiteri, Eduardo Paolozzi, Jack Vettriano, Nicola Benedetti - so many of them have become successes." The story begins much earlier, however. Roman legions arrived in Scotland in AD71 and left in 213. Southern Scotland was for a brief moment brought into Rome's vast empire when the Antonine Wall was erected across what is now the Central Belt. After Hadrian's death in 138 his successor, Antoninus Pius, abandoned Hadrian's Wall, which had just been finished, and ordered another wall to be built, 75 miles north, which would serve as both frontier and line of military defence. The Caledonian tribes, the Romans felt, needed to be kept under control.

The wall was abandoned just 20 years later but even today its crumbling remains can be traced along the area, 60 kilometres long, that divides the Firth of Forth from the Firth of Clyde. Its name survives in street names. Its course survives in mounds, ditches, and piles of rock. Its artefacts are held in the Hunterian. The Antonine Wall, which gained Unesco World Heritage status just two years ago, is considered to be the most complex frontier erected by the Romans.

Sally-Anne Coupar, curator at the Hunterian, is on her way to Edinburgh in a lorry with the marble Altar to Fortuna, recovered from Castlecary Fort along the Antonine Wall's line and dedicated by the Second and Sixth Legions to the Roman goddess of Fortune. "The Altar to Fortuna shows a long-term presence in Scotland, that the Romans brought their religious beliefs with them and set up altars so they could get their gods to watch over them," she says. "It's a lovely personal link."

"There is the head of a goddess recovered from a bathhouse in Bearsden fort," says Papadia. "It's very interesting and rare because it is a mixture of Roman and Celtic craftsmanship. It bears all the signs of a local artist."

The antiquarian links between Scotland and Rome are also important. Coupar takes me through the Hunterian's impressive coin collection, much of it belonging to 18th-century Scots physician William Hunter.

"We're one of the world's leading coin collectors," she explains. "Hunter's entire collection is with us. We recently loaned a coin to the Colosseum in Rome because the only surviving example was here in Glasgow. Hunter was like the godfather, a man who would make people an offer they couldn't refuse. He was extremely wealthy and would buy whole collections off impoverished counts. Some of these coins have never been displayed before."

Two manuscripts from the Scottish Catholic Archives have also never been shown. The Arma Christi (Instruments of Passion) is a 15th-century roll of four membranes that would have been used as an aid to spiritual contemplation. The Bull of Canonisation of John Ogilvie (1976) is a charter of the Banffshire-born saint who trained to become a Catholic priest in France and was ordained in 1613 and hanged two years later.From the Faculty of Advocates comes Emperor Justinian's Digest of Roman Law (1514), which forms the basis of Scots law. "Scotland, over time, developed a legal system very much derived from Roman law," Papadia argues.

"It's rather remarkable. Of course, it is not an entirely Roman system but it has an important Roman derivation that you don't find in the Common law system adopted in the rest of the UK. This volume was actually used as a main source for students studying law in Scotland at the time."

At the National Galleries of Scotland, Aidan Weston-Lewis, senior curator of Italian and Spanish art, talks me through the paintings donated to the exhibition.

"Many Scottish artists spent time in Rome in the days of the Grand Tour," he explains of the tourism that flourished in the 18th and 19th centuries when upper-class Brits, invariably men, toured Europe as part of their education.

"There were streams of Scottish aristocrats who headed off to Rome, had themselves portrayed by Italian artists, and brought Roman art and antiquities back."

A painting by Scottish neoclassical history painter Gavin Hamilton is included, depicting the Duke of Hamilton on his Grand Tour, accompanied by his tutor, physician and his physician's son. Hamilton, educated at Glasgow University, went to Rome in 1748 and studied under the Rococo painter Agostino Masucci.

"Hamilton spent most of his life in Rome," explains Weston-Lewis. "He became one of the leading art dealers and a famed guide. Scots visiting Rome on their Grand Tours would contact him and he'd take them round the classical sites.

"The mainstay of Scottish art was portraiture and some landscapes. The influence of the Italian tradition of paintings of religious and historical subjects in the grand manner started to be seen in Scotland in the likes of Hamilton's paintings. Experiencing Italian culture inspired Scottish artists to tackle more ambitious themes."

What about the 21st century? Steven McIver, from Orkney, is one of two contemporary artists with work in the show. How much of a link does he feel with Rome?

"Rome has been a massive influence on my work," he says. He won the Sainsbury Scholarship and spent two years at the British School at Rome in 2004. "In Rome I started using little scalpels to scratch layers of paint off the canvas. I saw it almost as a process of excavation, which seemed to fit with the layers of Rome."

McIver also completed an ambitious project that saw him travel around the world heading due west on the line of latitude on which Rome lies. "It's about the awareness of the history of Rome," he says of the project. "That vast empire, the sense that all roads lead back there." Was it always a one-way street, or did Scotland influence Rome too? The Scots College was established in Rome in 1600 to provide an education for the sons of Catholic gentlemen. And in the 18th century the Jacobites arrived in the Holy City."I suppose one could say the impact of Scots on Italy was less than that of Italy on Scots," says Weston-Lewis. "It was fairly one-way. But then you do have the Jacobites, an exiled Stuart court and all its attendees living in a Roman palace. They became celebrities for people on Grand Tours."

Today, the Roman influence can be seen all over Scotland. It's in the neoclassical buildings of Robert Adam, the architect who trained in Rome under Giovanni Battista Piranesi and designed Edinburgh's City Chambers, Old College and Glasgow's Royal Infirmary. It's in the delis and the throngs of Italian tourists who arrive every summer. It's in the landscapes and the religion. It's in the fact that Coupar says "when Scotland isn't playing we support Italy in the football".

Could we start describing Edinburgh as the Rome, not the Athens, of the north? "Well, the strong Greek neoclassical influence could equally come from Rome," says Weston-Lewis, "Right now I'm looking out of my window at the Bank of Scotland building on the Mound and it's very closely inspired by Roman Baroque churches of the 1830s and 1840s. And the influence goes on. Artists keep going to Rome. If it's not too much of a mixed metaphor, Italy and Rome remain a mecca for Scottish artists and tourists even today."

• Scotland and Rome, Centuries of Enrichment, opens at the RSA library today and runs until 30 September