The internationally-famous Thetford Treasure includes some of the most impressive Roman objects ever found in Britain and an exhibition of some of the highlights at the town’s Ancient House Museum has been extended for three months.

The hoard is believed to have been buried on Gallows Hill, Thetford, more than 1,600 years ago - either as an offering to Roman gods or for safe-keeping as the empire collapsed.

It was unearthed by metal detectorists in 1979 but the discovery was mired in controversy. The detectorists had no permission to be on the site and failed to tell the authorities what they had unearthed from land owned by Breckland District Council and being cleared to build the Fison Way industrial estate.

Instead they took the hoard home and it was kept in a bank vault for six months. By the time experts were alerted the land had been built over and there was no chance to discover more about the site and its remarkable treasures.

What they found, in a shale jewellery box, has been called the best-preserved collection of Roman jewellery from the western empire. It includes 44 pieces of intricate and beautifully jewellery made with gold beads and wire and precious stones, plus 33 silver spoons. It was declared treasure trove and bought by the British Museum in 1981.

The 11 exquisitely decorated treasures back on show in Thetford include a gold belt-buckle, a gold chain necklace, gold bracelets, gold finger rings, a pendant, a silver strainer and inscribed silver spoons.

Many have pictures and inscriptions linked to Roman gods Faunus, Bacchus and Diana and Thetford museum curator Oliver Bone said: “The treasure was buried in around 390AD when opposition to religious cults was rife.”

The exhibition also includes major finds of Roman pewter and glass from a Roman temple site in Hockwold-cum-Wilton, 10 miles from Thetford, and Oliver said: “Other objects in the exhibition highlight the importance of recording archaeological discoveries in helping us understand our past, using the Portable Antiquities Scheme.”

The exhibition, bringing part of the Thetford Treasure back to Norfolk, was due to close at the end of January but will now stay at the town’s Ancient House Museum until April 30 before returning to the British Museum in London.

“People have really enjoyed the display,” said Oliver. “We are hopeful that the spring weather will encourage more visitors to come to Ancient House to enjoy these special objects.”

The next major exhibition at Thetford’s Ancient House Museum will focus on the area’s Viking history. Visitors will be able to find out about the Viking invasion and how the Great Viking Army holed up for the winter in Thetford and learn about Viking-era Thetford and the attacks on the town just over 1,000 years ago by King Swein Forkbeard.

Objects on display from the British Museum will include brooches and a sword from a Viking-period burial at Santon, near Thetford, and a gold plaque from the time of the first Viking attacks, found at Brandon.

The year-long exhibition The Vikings, History on Your Doorstep begins on July 16 and is part of the Brecks Fen Edge and River project, with funding from the National Lottery.

The Ancient House Museum of Thetford Life, White Hart Street, Thetford, is open Tuesday to Saturday 10am-4pm.

Responsible archaeology

For many centuries Norfolk was one of the wealthiest and most densely populated places in Britain and more archaeological treasure is found here than almost anywhere else.

Anyone searching land must have permission from the landowner. This applies to commons, footpaths and beaches too. Objects which may qualify as treasure must be reported to the coroner for the area where the object was found, within 14 days of the discovery or identification. Failure to do so is a criminal offence. For information on what finds might be treasure and how to report it visit the Portable Antiquities Scheme website

Where to see more of Roman Norfolk

Forts. A chain of coastal forts was built almost 2,000 years ago to protect against raids from the sea. Two, at Caister on Sea and Burgh Castle, guarded the entrance to the estuary where Yarmouth now stands. There was another at Brancaster.

Roads. One of the main Roman routes into Norfolk from the south was along Peddars Way. It was already ancient 2,000 years ago. A line of grand Roman villas stretched along the road, complete with bath houses, mosaics and wall paintings. Archaeologists believe there was probably a ferry in Roman times, connecting Holme across the Wash to Lincolnshire. Long stretches of the A140 following in the route of Roman armies and administrators from Colchester to Caistor St Edmund. From the west, the Romans would have marched across the Fen Causeway to Denver.

Towns. Caistor St Edmund is one of just three regional Roman centres in Britain which have not been built over. Called Venta Icenorum by the Romans it had a forum, temples, baths, an amphitheatre, running water and defensive walls and ramparts.

Industry. Tiny Brampton, between Aylsham and Buxton, was once an important manufacturing centre – producing pottery and leather. Outside its earth walls were potteries with 132 kilns producing plates, bowls, jugs and jars.

Roman recycling. Thin Roman bricks in the walls of medieval churches reveal there were once Roman buildings near churches including Brampton, Burgh Castle, Houghton-on-the-Hill, and Reedham. At Reedham the churchyard conceals the foundations of a substantial Roman building - perhaps a fort and port, and possibly a lighthouse too, as the open sea washed as far inland as Acle and Reedham, along today’s Yare valley.

Statues. Not all our Roman remains arrived in Norfolk almost 2,000 years ago. It was only 300 years ago that Thomas Coke, the first Earl of Leicester, toured Italy, and arrived home to Holkham with souvenirs including ancient Roman statues created between the first and third centuries AD – exactly when the Romans were over here. He built Holkham partly to house his collection and today the Statue Gallery is described as perhaps the most complete collection of classical statuary in a private house in Britain.