In windswept Northumberland, Max Davidson traces the rise and fall of an empire.
NOW you see it, now you don't. For one of the great monuments of the ancient world, stretching from the North Sea to the Solway Firth, Hadrian's Wall is strangely elusive. For most of its 117-kilometre length, it is a ghostly presence, a memory.
You come across the occasional cluster of stones but, then, nothing - just a few sheep grazing on a windswept hill or a solitary tree silhouetted against the grey sky.
"Are you sure this is the right way?" a man shouts to his wife, as they clamber up a muddy hillock into the teeth of the wind. Crows circle overhead. There is a smell of damp gorse.
Walkers in their thousands tramp the Hadrian's Wall Path through some of the most bleakly beautiful scenery in England but if they have come for the history and not just the views, they only get it in slivers.
At the Holmhead Guest House in Greenhead, 32 kilometres east of Carlisle, I am actually staying right on top of the old wall. The building - like the wall - is made of stones that would have been laid by Hadrian's legionnaires in the 2nd century AD. But the site has a chequered history. In between the Romans and me, the stones formed part of a 14th-century castle, built to repel raiders from the north.
The only visible proof that the Romans were ever here is a fragment of graffiti: "Civitas Dumnonii". The Dumnonii were people from the south-west of England, conscripted by the Romans to make repairs to the wall in the third century. This would have been their way of marking their presence - the way today's Sunderland or Newcastle United fans might mark their presence on the wall of the gents'.
For the archaeologically minded, turned on more by the minutiae of history than by spectacular, look-at-me monuments, Hadrian's Wall is a source of inexhaustible fascination. There are clues everywhere you look but some of them are so subtle that you can easily miss them.
Even armed with an archaeological map of Hadrian's Wall from English Heritage, the most detailed guide published yet, I find it hard to get my bearings. There is the scar of an old trench and the outline of a fort. But why did the Romans build the wall there? Why not 90 metres to the south, where the ground is higher? And how would they have got supplies to the soldiers manning the wall in winter, when the area must have been completely snow-bound?
At Vindolanda, on the site of an old Roman fort, archaeologists are busy unearthing answers to just such riddles. Excavations on the site began in the 1930s and are set to continue into the next century. Even on wet days, when Hadrian's builders would have skulked in their tents, you can see a small army of volunteers in anoraks, digging, digging, digging.
The work is unglamorous but it is bearing a rich harvest; indeed, the museum housing some of the treasures found at Vindolanda offers unrivalled glimpses of daily life in Roman Britain, from mason's hammers to painted glasses, from the remains of a chicken supper to the tombstone of a man who died at the age of 24.
The most touching exhibits are the writing tablets. No texts or emails for these homesick Romans. They had to carve their messages, word by painstaking word, with styluses. But the content of the messages is timeless. A soldier puts in a request for leave. A quartermaster warns that supplies of beer are running low. A commanding officer sends new year's greetings to a friend in Rome. Claudia Severa invites Sulpicia Lepidaria to a birthday party. Suddenly these windswept Northumberland hills don't seem so remote from civilisation after all.
If Vindolanda is the archaeological jewel in the crown, there are other museums and visitor sites dotted across the region, from Tullie House Museum in Carlisle, which offers a good general introduction to Hadrian's Wall, to the Roman Army Museum near Greenhead, which recreates the daily life of the legionnaires, to Housesteads, the ruins of Vercovicium, one of the old Roman forts, which formed a chain right along the wall.
It is a peaceful spot today, set high on a ridge with views for kilometres around. Sheep graze undisturbed in what would once have been the home of the officer commanding the garrison. In the second century, at the apogee of Roman power, there would have been a thousand infantrymen here, most of them from what is now Belgium.
It is an extraordinary figure and becomes more extraordinary the more you think about it. Modern superstates still project their power overseas. Even as I stand in the Roman ruins, a Chinook helicopter on an army exercise roars overhead. But a thousand men? In this godforsaken spot, with the wind howling and nothing but the birds for company? Just to keep out a few long-haired "savages"?
Tourist buses ply the area, particularly in high season, but this is walkers' territory par excellence: a wonderland of gentle hills crisscrossed by dry-stone walls and the odd pockmarked B-road.
It is hard to think of a part of England quite so unspoilt. Livestock comfortably outnumber humans and, as the afternoon sun falls on the bare hills, the palette of colours, from slate-grey to a deep purple, is as rich as anything in Tuscany.
Many of the people I talk to are walking the whole length of the wall, rucksacks on backs, allowing anything from five days to two weeks. Sheila, from Amsterdam, is doing the walk for the second time, while a quartet from Melbourne, improbably, are raving about the pleasures of the British weather.
At one kissing gate, I come across a middle-aged French couple who, charmed by this ancient British institution, have decided to kiss each other at every gate they pass through, holding up the walkers behind them.
The central stretch of Hadrian's Wall is so sparsely populated that pubs and hotels are in short supply but that is all part of the charm of the region. You come across the same people again and again, whether you are traversing the wall by car or on foot. There is a real sense of community, as there would have been in Roman times.
At Greenhead, where the Hadrian's Wall Path going east-west crosses the Pennine Way going north-south, the village pub is like an airport terminal, packed with travellers heading in different directions with different tales to tell.
I team up with a couple of social workers from Leeds for the Wednesday night quiz and, had
I known the name of the second-highest mountain in Scotland (Ben Macdui), we would have scooped the pool. Revelling continues late into the night - not quite a Roman orgy but getting there.
My last port of call - Wallsend, a nondescript suburb of Newcastle - could hardly form a greater contrast to the bare hills of Northumberland. But even here, at Segedunum, the site of the old Roman fort, the legionnaires left their mark.
In the lovingly reconstructed bathhouse, with its cold room (frigidarium), warm room (tepidarium) and steaming hot room (caldarium), one can glimpse an entire social world, in which work and leisure both played a part.
As you stand in the ruins of the old fort, overlooking the shipyards of the Tyne, with a municipal bus disgorging its passengers in the background, any sense of emotional connection with the distant dead is only fleeting.
But for the small boy in the museum shop whose parents have bought him a Roman helmet, the past is very much alive. He puts it on, brandishes an imaginary sword and mutters something in Latin. He is living the dream.
Hadrian would have been proud of him.
Qantas/BA, Malaysia Airlines, Virgin Atlantic and Singapore Airlines fly from Sydney to Manchester, with stopovers. 13 31 33, flightcentre.com.au. Hadrian's Wall is about a 2½-hour drive from Manchester on the M6 motorway to Carlisle. Or explore east to west, from Wallsend, Newcastle.
The Holmhead Guest House, at Greenhead near Brampton has double rooms priced from £36 ($59) a person a night, breakfast included. The guesthouse also has a self-catering cottage from £265 a week and a camping barn. +44 1697 747 402, bandbhadrianswall.com.
English Heritage's comprehensive archaeological map of Hadrian's Wall can be bought online at english-heritage.org.uk for £7.99. The website also has information about heritage sites in Hadrian's Wall Country, including Housesteads, an old Roman fort.
Vindolanda has ongoing excavations and the Roman Army Museum also exhibits key finds. They come under the auspices of the Chesterholm Museum, Hexham, Northumberland. +44 1434 344 277, vindolanda.com. Tickets cost £5.90/£4.50 adults, £3.50/£2.50 children. Both Vindolanda and the Roman Museum are generally open seven days a week between 10am and 6pm, however both will have staggered closures between November and March to allow for refurbishment. Check the site for these times.
The Tullie House Museum, Castle Street, Carlisle, is open daily. +44 1228 618 718, tulliehouse.co.uk.
For information about Segedunum, the Roman fort and baths in Wallsend, Newcastle, see twmuseums.org.uk/segedunum.