Carlisle has been a bone of contention for centuries due to its strategic position as the gateway to Scotland. It has seen the Romans come and go, William Wallace, Robert the Bruce, Bonnie Prince Charlie, and the notorious Border “reivers”, who terrorised the Debatable Lands - border country - from the 14th to the late-17th century. But nowadays, the city is invaded by nothing more threatening than marauding hordes of children plundering its rich heritage, or using it as a bridgehead for wider exploration.

Dominating the city is the castle, constructed of the distinctive red sandstone characteristic of Carlisle from the old city walls and citadel to the new extension at Tullie House Museum. From the massive Norman keep, built in Henry I’s time, are panoramic views to the Lake District, Pennines, Solway Firth and Grampians. Robert the Bruce led a ferocious attack against it, Mary Queen of Scots was held captive here, and so were Jacobite prisoners following Bonnie Prince Charlie’s ultimately unsuccessful 1745-46 Rising, about which there is an exhibition (tel: 01228 591922).

Graffiti carved by 15th-century prisoners awaiting execution can be found in the dungeons and mysterious “licking stones”, which yielded enough moisture to keep Jacobite prisoners alive, only for them to be barbarically executed on Gallows Hill and their heads displayed on Scotch Gate.

Kinmont Willie, the head of the most feared reiving family, the Armstrongs, was also incarcerated in the castle - until his sons engineered his dramatic escape. The reivers’ bloodthirsty raids on homes and livestock bequeathed a lasting legacy to the language - the words “bereaved” and “blackmail” - since they left many grieving widows in their wake and forced people to pay protection money (“greenmail” being the rent payable to a landowner).

These stories are compellingly told in a sound and light show in Tullie House Museum, using the words of ballad singers and the Borderers themselves. You can even discover whether you have a villainous ancestor among the 77 reiving families on archive there - to my shame, the Halls loom large on the list. There are also imaginative displays on the Romans, the Dark Ages, the English Civil War, the railways and wildlife. Activities include querning the grain, shooting a Roman crossbow, writing on Roman wax tablets and roleplay sessions (tel: 01228 34781).

Many visitors head for the Lakes, but a rewarding alternative is a trip on the Settle-Carlisle Railway through the Eden valley and Yorkshire Dales to Ribblehead Viaduct. The journey takes an hour-and-a-half, so keep the children occupied checking off tunnels and viaducts. The skilled Victorian engineers constructed 14 tunnels and 20 viaducts in the space of 72 miles to forge the line through high hills, deep valleys, great rock scars, peat bogs, pot holes and boulder clay. Or regale them with some of the remarkable, tragic and humorous stories of the line’s history, the navvies who built it and its porters and signalmen.

After marvelling at Ribblehead’s 24 soaring arches, you can be met by coach by prior arrangement, taken to Hawes and Pendragon Castle, and delivered to Appleby station for the return journey. Tracks North offers the entire traincoach trip plus guide, David Alison, for about Pounds 10 a head (tel: 01539 824666). Any other itinerary can be arranged.

At Hawes, visitors can find out how the twist is put in a rope at Outhwaite Sons Ropeworks. Skipping, church bell, bannister and barrier ropes, colourful Harlequin dog leads and clotheslines are all made here. Admission is free. You can also discover the story of local people and the landscape at the Dales Countryside Museum (tel: 01969 667450), and see how cheese is made at the Wensleydale Creamery Visitor Centre (tel: 01969 667664).

King Arthur is said to have been born and brought up at Pendragon Castle, built by his father, Uther Pendragon. Standing in solitary splendour, it is beautifully compact with vaulted chambers, spiral staircases, a deep moat and the remains of the tall tower one medieval owner had built for her own quarters. According to David Alison, “the present owners do not object to the occasional school party clambering over the battlements”.

For a less ambitious excursion, strike out 16 miles east of Carlisle to Birdoswald Roman Fort. Perched high on a cliff above the Irthing Gorge, it forms part of Hadrian’s Wall, the great barrier the Roman emperor built in 122 to keep out the “barbarians”, and has been occupied almost continually for 2,000 years. Besides Roman remains, cross-sectional excavations have uncovered evidence of medieval granaries, and there is a fortified 16th-century farmhouse and high Victorian tower. Admission is 75p a head (tel: 016977 47602).

To get an insight into medieval religious life drop in at Lanercost Priory. Founded by Augustinian canons in 1166 using stone pillaged from the Wall, it was the base of Edward I for his regular forays to “hammer” the Scots (tel: 016977 3030).

Accommodation is available in youth hostels which include Greenhead, Carlisle, and several along the Settle-Carlisle Railway. Full board costs about Pounds 15 a night.

Carlisle Visitor Information Centre, tel: 01228 512444 Carlisle Tourism and Marketing (guided tours), tel: 01228 33681 Settle-Carlisle Railway Development Company, tel: 01729 822007 Youth Hostels Association (for the north), tel: 01629 825850