Three days in Uppsala: Scandinavia's oldest university, and the pagan kings buried up the road

The cathedral is visible from most of the county and is the tallest church in Scandinavia, with twin spires that are exactly as high as the building is long. Building started in 1272 and finished in 1435, in French Gothic brick, and it is still the seat of the archbishop and the place Swedish monarchs were crowned for three centuries. Gustav Vasa, the king who broke with Rome and made Sweden a country, lies in a chapel at the east end between his first two wives, under national romantic frescoes painted in the 1890s telling the story of his reign in the way the nineteenth century preferred it. Carl Linnaeus is under a slab in the floor of the nave. So is Emanuel Swedenborg, who spent the first half of his life as a mining engineer and the second half talking to angels.

The relics of Erik the Holy, a twelfth century king killed coming out of mass in Uppsala, are kept in a gilded reliquary. He is the patron saint of Stockholm and there is no good evidence he was ever canonised.

Then Gustavianum, across the square, which is the oldest surviving university building and now its museum. Under the strange onion dome on the roof sits a wooden theatre built in the 1660s for public dissections: a steep funnel of standing galleries around a central table, so that medical students could look down on the work. The bodies were those of executed criminals and it was only used in winter. Downstairs is the Augsburg Art Cabinet, a black ebony chest made in 1632 and given to Gustavus Adolphus, containing about a thousand objects, automata, instruments, curiosities and games, all fitted into one piece of furniture that cost roughly what a palace cost. There are also Egyptian mummies, and the boat burials from Valsgärde up the river.

Gamla Uppsala is fifteen minutes north on the bus and is where all of this started. Three enormous burial mounds stand in a row in open ground, each about ten metres high and sixty across, raised in the sixth century over cremations rich enough that the people under them were certainly royal. Local tradition assigns them to Odin, Thor and Freyr, which is later invention; the archaeology says a man, a woman and a third burial, with gold, garnets, weapons and the bones of falcons and dogs. You can walk up them.

Around 1070 a German cleric called Adam of Bremen described a temple here roofed in gold, with a grove beside it where the bodies of men, horses and dogs hung from the trees, and a great sacrifice held every nine years. He had not been to Sweden. Whether any of it is true is the oldest argument in Swedish archaeology, and the honest answer is that a very large hall did stand on this ridge and nobody knows what happened in it.

The church next to the mounds is twelfth century and is what is left of a much larger cathedral that burnt: this was the seat of the Swedish archbishop from 1164 until the see moved down to the new Uppsala in 1273. Anders Celsius, who devised the temperature scale and got it the right way up on the second attempt, is buried inside.

The museum by the mounds holds the finds and does the interpretation carefully rather than dramatically. Then walk ten minutes to Disagården, an open air museum of relocated Uppland farm buildings arranged as a nineteenth century village, where the interiors open only for the daily guided visits in the early afternoon.

Carl Linnaeus arrived in Uppsala as a student with almost no money, became professor of medicine and botany, and worked out the system of two part Latin names that every living thing on earth is still filed under. He also sent nineteen of his students out on ships to collect plants, of whom seven did not come back.

His garden is a ten minute walk north of the centre. It was first planted in 1655 by Olof Rudbeck, ran down, and was rebuilt by Linnaeus from 1745 into a living demonstration of his classification, with the beds laid out by the number of stamens. It was restored in the 1920s to the plan Linnaeus himself drew, so the arrangement you walk through is his. The house at the southern corner is where the family lived from 1743, and it is furnished as it was.

Walk back south and up onto the ridge for the castle, a pink Vasa fortress begun in the 1540s, badly damaged by the city fire of 1702 and rebuilt smaller. It is the county governor's residence and holds a couple of museums, but the reason to walk up is the terrace, which gives you the cathedral, the water and the roofs in one view.

Directly below the castle is the university's main botanic garden, planted in 1664 as the castle's own and given to the university in 1787: a formal baroque parterre climbing towards the castle wall, an orangery, and a tropical house. The station is fifteen minutes' walk from the gate.