Double vision: cover two of England's great cathedral cities in a single trip

Gothic or Norman? Whatever your preference in terms of church architecture, it is difficult not to be impressed as you stand in front of York Minster, looking up at the great rose window that depicts the red and white roses of York and Lancaster, or contemplate the vast door of Durham cathedral, where fugitives would knock when they came in search of sanctuary.

Durham is the more ancient of the two buildings, constructed to house the body of St Cuthbert when a Viking invasion drove the monks of Lindisfarne to seek a safer haven further south. They found themselves at a steep peninsula, its wooded banks surrounded on three sides by the river Wear, and this was where they built a simple church at which pilgrims could worship. It lasted until the Norman conquest when a community of Benedictine monks settled on Dunholm, the hill island, and over the course of 40 years, a magnificent cathedral was built. Around it existed a whole monastic structure, and much of this still forms the heart of Durham. Attached to the cathedral is a lovely cloister; upstairs, the monks' former dormitory now houses part of the cathedral library; and the undercroft has been turned into a restaurant.

The Normans saw the benefit of the peninsula as a strategic location, and built a castle there too, opposite the cathedral on the other side of a grassy space now known as Palace Green. Durham became a palatinate, ruled by Prince-Bishops who were originally installed in the city to run the place, combining a secular and religious authority that was gradually eroded over the succeeding centuries. In 1836, shortly after the university was founded, the role of the bishop became purely ecclesiastical and the castle building was handed over to the students. Some of them still live there, in accommodation that must surely be more atmospheric, if not luxurious, than anywhere they are likely to dwell in the future. The best way to see the castle is to befriend a resident, but there is also limited access for visitors on guided tours.

William the Conqueror built a castle in York, too, but its structure fared less well. All that remains is Clifford's Tower, a later addition built by Henry III. In the 18th century the area was redeveloped, creating a crown court and two prison buildings. These Georgian buildings now house one of York's finest attractions, the Castle Museum, where the city's Victorian and Edwardian history comes to life through period rooms and reconstructed cobbled streets.

The Georgian period left its mark on both cities. In Durham it is most notable along the North and South Baileys, which, with Saddler Street and the old market place, still form the city centre's main artery.

The first residents of the Baileys were the grandees of the bishopric, later replaced by affluent local citizens who wanted elegant townhouses. Most of the buildings are now the property of the university, housing several academic departments and a considerable number of students.

Other elegant Georgian properties line South Street, perched on top of a wooded bank to the west of the peninsula from where there are stunning views of the cathedral. Recently, one of these has been turned into a boutique hotel, Grafton House, filling a much-needed gap in the accommodation market.

In contrast, York has a number of historic buildings that now provide accommodation, including the Judges Lodgings; and from summer next year, Gray's Court, the original Treasurer's House, will also open as a small hotel.

It is easy to assume that all of Durham's heritage is concentrated around the castle and cathedral, but to many people unconnected with the university or the church, Durham was a coal-mining town. The last colliery within the city boundaries – although beyond the confines of the peninsula – was Aykley Heads, which closed in 1949. Its buildings are under the car park of the Durham Light Infantry Museum, the pit shaft has been capped and is hidden by a clump of trees, and the colliery pond is now a feature of a landscaped nature walk. Like the Durham mining industry, the DLI has also ceased to exist, after serving its country in action around the world, from the Crimea to Borneo. The museum is a fascinating spot, and the displays and memorabilia reveal some poignant personal stories. In one display case is a letter from the front sent in 1914 – beginning "Dear Wife" and ending "Your Hubby". It was placed in a bottle, and although the wife never did receive it, it was finally washed up in the Thames in 1999.

While Durham had the natural barrier of the river Wear to protect it, York had to build its own defences, and one of the most striking features of the city is its walls, two and a half miles of stone that form an almost complete circle around a settlement that was first colonised by the Romans.

Most of York's present walls are medieval – although the thrifty Normans reused some of the Roman stone – but they are astonishingly well-preserved, with four of the five original bars, or gates, still standing. The northern entrance was Bootham Bar, a squat, square tower with round turrets on each corner.

A plaque on one side of the archway points out that this was also the site of the Porta Principalis Dextra, the north-west gate of the Roman fortress, and Roman traces are on view all over the city. Don't imagine that the Roman Bath tavern got its name as a gimmick; this popular watering hole shares its premises with a real historical relic. Buy a ticket at the bar along with your drink, and pop downstairs to see a bath house that once belonged to the Ninth Legion.

The Vikings came next, their legacy largely preserved in the road names. "Gate" was their word for street, and anything with this name – such as Petergate or Fossgate – is likely to date from the 10th or 11th centuries. The Viking lifestyle is best experienced at Jorvik, built on the site of an excavation that took place some 30 years ago and where visitors can experience life as it would have been under the Nordic invaders. Close by, but altogether more opulent that anything the Vikings could have imagined, is Fairfax House. Thought by some to be the finest Georgian house in England, it fell into disrepair but was rescued and renovated in the Eighties. By a happy coincidence, the collection of Georgian furniture amassed by Noel Terry, heir to the local Terry's chocolate empire, needed a home, so the two are now displayed together, surroundings and contents complementing each other beautifully.

Durham may lack anything as grand as Fairfax House, but it does have a hidden gem, a treasure so secret that even many local residents are unaware of its existence. Crook Hall is little more than a mile from the city centre. The house itself is privately owned, a curious mixture of medieval, Jacobean and Georgian architecture; the medieval hall, with its sturdy beams and minstrels' gallery is open to visitors, as is the Georgian dining room which is now a tearoom. But the real delight is the garden: a series of secret spaces, some of them walled, linked by gates and arches. The most tranquil spot is the cathedral garden, whose beds and hedges are designed to represent stained glass windows. Straight ahead, providing inspiration for both the garden and those who visit the city, are the stones of Durham cathedral.

Cathy Packe travelled with National Express East Coast (08457 225 225; www.nationalexpresseastcoast.com). Advance return fares between London King's Cross and Durham start at £23 when booked online.

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