It must be such fun whenever Heilung go through an airport. Among the various horns and antlers that make up their onstage headgear, the Danish-Norwegian-German folk collective also carry with them drums made from the skins of deer and goats. The one they have made of horse skin has the added bonus of being baptised in the blood of the band’s core members. Obviously, it would be rude to hit such an instrument with anything less than an arm bone, so they carry one of those with them, too. By this point, one imagines, the customs officer has already guessed that one of the shakers contains – what else? – human ashes.

Heilung couldn’t really do what they do without them, though. What they play is ceremonial folk descended from the earliest and most ancient forms of music. Much of it is based around hypnotic, repetitive rhythms, chanting and throat singing, and their focus is on returning to the most primal, earthy form of expression to reach a state more in tune with nature. One piece they’ve recorded is Hymn to Nikkal, believed to be the world’s oldest song, dating back some 3,400 years, for which instructions on how to play on the lyre were found carved into the wall of a cave by archaeologists in the 1950s in what’s now Northern Syria.

Saturday night’s performance at the Apollo saw them bringing their grisly instruments, plus onstage trees, fire, nudity, spears and shields to a full house. The Heilung live experience is not a gig, insist the band, but “a ritual”. Appropriately, proceedings began with a hooded figure anointing the stage with incense, and a declaration that: “We are all descended from the one great spirit”. Equally appropriately, into the library quiet of this poignant opening moment, one voice in the audience could be heard appeasing the ancient gods in a more modern way: “Put your f---ing phones down”. 

If the idea that something so esoteric and challenging should have found success in venues this size seems unlikely, in practice Heilung are a much more digestible proposition than they might seem on paper. Occasionally, such as on Anoana, from last year’s Drif album, one might compare them to Enya. Largely, though, the compelling power of half a dozen people in ceremonial robes or stripped to the waist hammering out a beat as half a dozen more dance into a frenzy feels more like millennia-old dance music.

Certainly, it ain’t rock’n’roll. But then again, Heilung still convey that same awesome, thundering power as the loudest music from the past 70 years. When it hits right, you can feel them, appropriately enough, in your bones.

Touring the UK and Ireland until Jan 22, then abroad. Tickets: ticketmaster.co.uk