Siberia has never enjoyed a good press. We headline it as emptiness, a place of frigid exile, inhospitable both to the body and to the imagination. One of several wonderful things about this British Museum exhibition is that it gives the lie to that void. Siberia comes to life in dramatic, sometimes breathtaking ways: in fabulous gold and soft fur, in the insistent humanity of sticks of crafted furniture and clothes and food. That this life – leathery and intimate and horse-obsessed – is preserved from two and a half thousand years ago makes it all the more magical.

For most of that time the only real record of the culture of the Scythian people, nomadic tribes who herded cattle and goats on the grᴀssy corridor of the steppe, came in the writings of Herodotus, who pitched up in his travels on the north shore of the Black Sea some time around 440BC. He observed and wrote about the rituals and habits of a rugged and resourceful people who dominated a vast area for 500 years and who would continue to do so for a century or more to come.

It was not until the time of Peter the Great that those observations of Herodotus began to be verified by archaeological discovery. This exhibition, which wears its considerable scholarship lightly, begins by capturing the excitement when those first discoveries were brought to the Winter Palace in St Petersburg from southern Siberia. At first, when confronted with the solid gold belt plaques exquisitely rendered with scenes of battles between mythical and realistic animals – a dragon tearing into the flank of a horse, a jewelled vulture devouring a yak – the enlightened scholars of Peter’s court had no idea where these things came from or how old they were.

The Russians considered Siberia to have been a barbarous place, and these objects overturned that idea. When they were determined to be Scythian objects, a debate opened as to whether they were products of an oriental or a Slavic – Russian – civilisation. The more pressing question for anyone looking at these pieces of gold now – bold bracelets and delicate earrings and necklaces as well as the symbolic bling of belt buckles – is who were these cattle herders who left no written record of nearly a millennia of civilisation, but who could create such ornament?

Some very good answers to that question are provided by this show, which is the British Museum at its best – gathering the evidence from a mostly unknown time and place in antiquity and making it news. That task had a major stroke of historical fortune. When the graves in the Pazyryk valley in the Altai mountains were first robbed, water entered the underground burial chambers and remained permanently frozen, insulated by the mound of earth above. Wood, felt, silk, leather, human bodies and other organic matter buried in the fourth and fifth centuries BC remained intact until Russian archaeologists excavated the sites in the first half of the last century. More finds are still being made, an effort given greater urgency because of rising temperatures melting permafrost.

You get graphic evidence of this fact when you meet the shellacked gaze of a Scythian warlord, his head with skin and teeth intact, dug from a 2,400-year-old grave. The man survived some wounds – his forehead bears the traces of silk sutures – but was killed with three blows from a Scythian battle axe, an example of which is cruelly preserved opposite. Also on display are sections of the man’s crumpled skin with very contemporary looking sleeves of tattoos, the animalistic myths inked with soot.

The most extraordinary insight into of the lives of people like this man is then established in an array of objects defrosted from tombs. There are patterned felt textiles, including stockings in a shade of light tan, lovingly designed squirrel fur coats, appliqued with felt, a sable fur pouch and leather purse softened with use. In most displays of this antiquity you are restricted to the hard edges of bronze and pottery. These fabrics lend a more human touch, none more so than the strange false beard of real hair designed to be hooked over the ears, and the saddle bags containing a meal to take a Scythian chief through to eternity: coriander seeds, a sheep’s bone that once was a lump of mutton, and a small cloth bag containing lumps of Scythian cheese (best before 350BC).

Some of these objects, mostly borrowed from the State Hermitage Museum, were made with a sense of fierce display – an eagle-topped headdress, for example, carved from wood, decorated with leather and designed to rise a foot or more above the wearer’s head. More often they exhibit a keen utility – pots and stools and sticks of furniture are made for portability, iron age picnic sets for a community always on the move. Some of this travelling was also in the mind. Herodotus described some handy apparatus, made of a small wigwam of three sticks covered in felt inside which hemp seeds were burned on red H๏τ stones, and the smoke inhaled causing the Scythians to “howl with delight”. An example of this mini stoner’s paradise was also found among one chief’s essential grave artefacts.

The Scythians were an unrooted people and they borrowed and traded from their sedentary neighbouring cultures: there are Chinese silks, sleeves of Indian cotton, wine cups with a Greek cast. What this exhibition makes clear, however, is that they also had a sophisticated and mysterious culture of their own – grave decorations of men on horseback display not only a warlike tendency, but also a sense of humour and playfulness. You might, as I did, go into this exhibition thinking of ancient Siberian history as a fairly blank canvas; you will come out with a sense of it having been coloured in.