THOSE signs, the one those renegade historians have been shuffling around the countryside near the River Tees - why don't they say Durhamshire?

This baffled me, all those years ago, when I applied for a job on this newspaper. I came from a land of leafy shires - Hertfordshire, Bedfordshire, Buckinghamshire - yet this was a place somewhere in the distant cold north that sounded like it belonged in Ireland.

County Durham is the only county in England to call itself a county. It grew out of the ancient kingdom of Deira, which was all the land north of the Tees. The Earl of Northumberland was originally top dog, but gradually various kings gave bits of land to first St Cuthbert and then to the bishops that followed him.

When Earl Waltheof of Northumberland was executed for plotting against the king in 1075, the Bishop of Durham became both the spiritual and the political leader of the province.

Unfortunately, that Bishop of Durham was a fellow called William Walcher. His men were implicated in an unpopular murder at Lumley and, in revenge, the Bishop himself was brutally bludgeoned to death on the banks of the Tyne by his own flock.

Therefore, it is Walcher's successor, Bishop William St Carileph, who is generally recognised as the first "prince bishop". He was king of the county, raising armies, levying taxes, minting coins. In recognition of his special powers, when other more subservient counties were being called "shires", Durham was called a "county palatinate". And so we have County Durham rather than Durhamshire.

The geographical boundaries, though, of the 12th century palatinate are interesting, particularly when trying to work out where to place 21st century signs.

Initially, "the wapentake of Sadberge" was outside the Bishop's domain. Today, Sadberge is a little village whizzed passed by the A66, but 1,000 years ago it was the capital of a territory that ran from Middleton-in-Teesdale in the west to Hartlepool in the east.

"Wapentake" means "weapon-touching" which suggests that all the leading warriors from villages like Eggleston, Gainford, Hurworth and Egglescliffe came to Sadberge to clink their weapons together as a sign of allegiance.

Sadberge was an independent county until 1189 when King Richard the Lionheart, desperate for cash for his crusades, sold it to the Bishop of Durham for £11,000 (about £5m in today's prices).

Even under Durham's rule, it took centuries for Sadberge to lose all of its independence and to this day the Countess of Sadberge is none other than Queen Elizabeth II.

Although the towns of Darlington and Stockton were never under Sadberge's sway, there is a little historical legitimacy to the modern, widely-ridiculed, concept of the "Tees Valley".

The acquisition of Sadberge made the Prince Bishop of Durham lord of all the land between Tees and Tyne. He had other bizarre, unattached pockets of land called exclaves that were beyond the rivers.

The village of Crayke near Easingwold in what we would today consider to be Yorkshire was for 1,500 years County Durham. For 900 years, Bedlingtonshire, Norhamshire and the wonderfully-named Islandshire of Holy Island were also exclaves of County Durham. They were given to Northumbria in 1844 - only yesterday in the long sweep of history - when the early Victorians tidied up the county boundaries.

So perhaps we should start a campaign and demand their repatriation. We could put up nameboards in Northumbria declaring the historic Durhamness of Bedlington and Belford. Perhaps the villagers of Sadberge should re-awake their heritage and start wapping up "Welcome to the Wapentake" signs all over the Tees Valley.

That'd really confuse the visitor who doesn't know whether he is durham or going.