Environment Editor Tony Henderson seeks out the Place of the Roaring Stream.

If Hadrian's Wall was the eventual northernmost frontier of Roman expansion, then the fort of Bremenium was on the edge of the empire.

For more than 200 years, the fort, now the hamlet of High Rochester in Northumberland National Park, was the most northerly occupied base in the entire Roman empire.

It was a dicey place to be, as indicated by the fact that the garrison was provided with a giant catapult which fired heavy stone balls.

Two of the projectiles can be seen mounted on the corners of the porch of the former schoolhouse in the village of Rochester below the fort, which is built mainly from Roman stone.

After a short climb to Bremenium, visitors can wander around its perimeter walls to gain a sense of how wild this posting must have been, and how it retains an air of remoteness today.

The base is one of the fascinating features of Redesdale.

The valley of the River Rede is 37 miles long. The river rises on the slopes of Carter Fell on the Northumberland-Scotland border and eventually joins the North Tyne near Bellingham.

Bremenium means the Place of the Roaring Stream - a reference to the Sills Burn, whose deep and narrow valley threads through the landscape near the fort.

After prolonged heavy rain or a thaw, the Sills Burn can indeed make itself heard.

At other times, it makes a pretty picture with twin waterfalls and primrose-covered banks.

The fort occupies a strong position on a low hill with views over Upper Redesdale and beyond.

Recent research suggests that it was built on top of a previous native settlement - possibly a prestige Iron Age centre.

Remarkably, the site is included on Ptolemy's map of the ancient world, compiled in Alexandria in the Second Century, which perhaps indicates its importance as a pre-Roman centre.

The fort site was chosen by Julius Agricola, Roman Governor of Britain, in the late First Century as part of the thrust into Scotland.

Bremenium became an outpost fort beyond Hadrian's Wall - a sort of early warning station.

Today, there are houses inside the fort walls, including two 16th Century bastles, or fortified farmhouses.

Where the fort buildings stood is now known as the village green.

One of the fort's roles was to keep a wary eye on and gather intelligence about the tribes to the north of Hadrian's Wall.

It was also a staging post and guard base on the major military highway, called Dere Street, built by Agricola to carry the campaign into Scotland.

Up to 500 men were shoe-horned into Bremenium.

The earliest known garrison was a mixed infantry and cavalry regiment from about AD140, with the same sort of outfit in the Third Century.

Troops known from inscriptions were raised in France, Spain and Belgium.

An inscription also refers to the Bremenium Scouts, or Exploratores Bremenienses, who patrolled the surrounding lands.

The role of this unit is likened by Lindsay Allason-Jones to that of Indian scouts working for the cavalry in the American West.

Lindsay, director of archaeological museums at Newcastle University, says: "Most of the time, Bremenium was in barbarian territory.

"It also minded the army's back as the troops went up Dere Street."

Unlike other forts, where civilian settlements grew up outside the walls, there seems to have been little or nothing of this nature at Bremenium.

Even the bath house was inside the fort.

"It was always a dangerous place. It would have been fraught with hazards," says Lindsay.

"It was still a dodgy place up to the 18th Century." Hence the bastle houses.

In 1581, the Rochester villages lodged a complaint with Elizabeth I's commissioners against the Elliots of Liddesdale, who had raided on several occasions, taking livestock and household goods "so that the town was laid waste for five years".

Lindsay says: "The Redesdale baddies were all over the place.

"People were looking for somewhere defensible and the fort walls offered some protection."

Something of a siege mentality may be guessed from the fact that two double granaries in the fort could store large stocks of grain in times of emergencies or to supply units operating north of the Wall.

Multiple ramparts protected the fort, which could have accommodated up to 16 barracks tightly packed into a total fort area of just under five acres.

Although an outpost, the fort has yielded finds such as an altar to Minerva, an underfloor heating system, spring-fed baths and a stone panel carved with images of Venus washing her hair while attended by two nymphs.

The carving may have been used for the front of a water tank and was based on a Third Century BC Greek original.

"It was a famous depiction and would have been well-known in Rome.

"It looks like the person who carved it at Bremenium was told what to do and had never seen the original," says Lindsay.

"As a result, the ladies who are depicted have a very Celtic look.

"It was a frontier fort but they have gone to the trouble of carving this in classical style.

"Although it was a very dangerous place, they felt it was worth decorating."

Page 2: A lady waiting in nowhere