Not that its humble and sometimes disputed beginnings have ever bothered the proud citizens of Donaueschingen at all. The town, sitting prettily between the Black Forest and Lake Constance, has grown up at the point where the Brigach and Breg join to form the Danube. It's an amiable little place, with all its public buildings painted in pastel colours strongly reminiscent of sugared almonds. There is also a honey-coloured palace owned by the Duke of Furstenberg who has wisely thrown it open to the public and moved to a smaller residence in the town.
The Donauequelle spring itself, which rises in the palace gardens, has been thoughtfully provided with a balustraded basin and a group of allegorical figures in marble. And it features a scantily clad "young Danube" thinking about her long journey to the Black Sea.
From Donaueschingen the railway follows the river and between Beuron and Sigmaringen the single track is squeezed between the river and the rock in one of the great little rail journeys of the world. For the first few miles we bounced along beside the Danube which meanders through fields like any small, provincial stream. Then the train entered a tunnel and came out into a wilder and altogether more exciting place.
Limestone crags reared up on either side and there, spread in a vast amphitheatre of fields, was the great Cistercian abbey of Beuron. I alighted with a party of nuns and together we climbed the hill towards the abbey past frescoed pilgrimage houses.
I carried on down the hill across the covered wooden bridge which straddles the Danube to a lonely white house that sits at the bottom of the limestone cliff facing the abbey. This is the convent of Maria Trost, which takes in pilgrims on retreat and travellers coming to listen to the monks chanting vespers. I followed a silent, white figure to a cool room looking out to the abbey whose bells were already tolling.
I hurried back across the bridge to what is one of the great Baroque churches of Germany. The Cistercian monks filed into the choir stalls and took up the Gregorian chant which rolled around the interior and washed over the small congregation. Vespers over, I walked briskly back to Maria Trost for a supper of bread, cheese and hibiscus tea. The tea was very pink and the dining room was deserted. On the other side of the wall I could hear the nuns laughing as they washed up.
The next morning the valley was full of mist as though someone had poured milk into a bowl. By the time it had cleared, I had finished a breakfast of bread and honey and was ready to leave. It's an hour by train to Sigmaringen but what an hour! Here the line is squeezed between the cliff and the Danube. At times we seemed almost to brush the cliffside; at others we looked up at fresh, creamy scars with the crumbled rock piled beside the track.
The crags dwindled and died out, the Danube broadened and swept on to Sigmaringen. Its castle looms over the river, a huge, medieval place, transformed in the 19th century so that inside it is all gilt and red velvet. It had a Saturday market at its feet, with stalls selling apples and pumpkins, honey and cheese. I took a roll filled with hot sausage and a couple of apples and walked along the banks of the Danube, which flowed on, blue beneath a blue sky.
Getting there: the writer paid a total of pounds 202 by rail from London to Donaueschingen and back, made up as follows: Eurostar London-Cologne return pounds 89 (six hours); Deutsche Bahn Cologne-Donaueschingen return pounds 99 (five hours 15 minutes); Donaueschingen-Sigmaringen return pounds 14. All fares can be booked through Deutsche Bahn (0171-317 0919).
Donaueschingen is relatively well off for hotels, guest houses and private B&Bs, including some luxurious hotels for which, however, you would need a car. The Hotel Gasthof zum Hirschen (00 49 771 2549, fax 00 49 771 7859) is a small, reasonably priced hotel with very good regional food. The local tourist office (00 49 771 857221223, fax 00 49 771 857228) will help with booking.
In Beuron, Maria Trost (fax 00 49 771 746 6483, it's best to write in German) is by far the most atmospheric place to stay and very reasonable. If you don't speak German, book through the local tourist office (00 49 7466 214).
Moswin Tours (0116 271 4982) offers tailor-made tours around the young Danube.