Unique conditions preserve treasures

Photo is Laurie Walker and Bob Hefford.

Photo is Laurie Walker and Bob Hefford.

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Morpeth rotary club

Dr Bob Hefford is a chemist and cosmetic scientist, but on his days off he spends a lot of time at Vindolanda Roman Fort.

His special interest is vivianite, a vivid blue iron phosphate. It appears to have something to do with the wonderful way that materials are preserved at the site.

Following Dr Hefford’s PhD at Leeds University, he married a Northumberland girl and moved North. For around seven years he has been helping with excavations at what he considers to be the most important Roman site in Western Europe.

Vindolanda is a Roman auxiliary fort on Stanegate, the road from Carlisle to Corbridge. Soldiers were not legionaries, although some would have stayed here as three Roman Legions were used to build the Wall. Stanegate was guarded by forts each a day’s march, 30 miles, from the next. The fort was manned by Batavians and Thuringians, who were from marshes near the Rhine. It was manned until 410, but continued as an occupied site until the sixth century and probably later.

Towards the end of the Roman period a temple was knocked down and became a Christian church.

The foundations are a layer of nine earlier forts. It is most famous for the wooden tablets/letters that were preserved — 30,000, written between 220-230, were found under what was a car park. There is probably enough to justify another 150 years of excavation. Items found here would have decomposed elsewhere. Wood, metal, textiles and leatherwork is all well preserved due to a combination of dampness, low temperature, lack of oxygen and chemicals in the ground.

The first fort was built of wood. The Batavians were good at crossing rivers in full armour on horses so when Trajan went to fight against the Dacians of Romania he took them along. It was the practice to demolish a fort after use. Records would be thrown into a trench and burnt. When they left, they piled all of the records in a pit and set fire to them, but a storm must have put it out and they were left in a trench sealed with clay.

One letter is from the commander’s wife to the wife of another commander to invite her to a birthday party. Another was a list of everyone at the fort on one particular day.

Ten years ago three bore holes were made and temperature, acidity and other soil conditions measured. Vivianite can be used to coat iron so that rust does not attack. Heather and rushes were used on floors, which produced tannin, which also helps to preserve.

Usually shoes do not last, but 3,000 have been found here. Each costs £30 to preserve. A total of 21 silver pieces were found in a bag under a flagstone, and one gold coin. The skull of a man from Scotland was found with sword cuts to the head and signs that it had been placed on a pole. There was a skeleton of a girl aged around ten and probably from North Africa.

Hadrian visited the Wall and remains have been found of a large house nearby, which could be where he stayed.

The Roman Wall was abandoned when the Antonine Wall was built in Scotland. It is now an English Heritage site, but in earlier times farmers could pay to take large blocks of masonry and walls away.

Laurie Walker gave the vote of thanks.