Few bands can boast a trajectory as coherent as that of Enslaved. Born in the early 1990s in the — sometimes sulphurous — ferment of the Norwegian black-metal scene, the Bergen outfit refused from their earliest records to be confined by it. Thirty years on, Heimdal, their sixteenth album, extends that headlong flight: a work that draws from Norse mythology the material for a progressive metal of uncommon richness.

The critics, out in force (an 84 average across ten reviews), hail a mastery become second nature. In Enslaved, the black metal of the origins has not vanished: it surfaces in the glacial tremolos, in certain guttural flashes. But it now cohabits with atmospheric keyboards, near-psychedelic clean vocals, a song structure that owes as much to Pink Floyd as to Bathory.

Heimdal — named for the god who guards the Bifröst, watchman at the border of worlds — assumes that threshold position. The record is a bridge: between fury and contemplation, between the archaic and the modern, between myth and introspection. The compositions take their time to unfold, to breathe, to build sonic cathedrals in which the listener can get lost.

Some will regret that the band no longer surprises as it did in its great hours of mutation. The reproach is fair: Enslaved have found their formula and refine it more than they reinvent it. But that formula remains of rare elegance, and rare too are the veterans capable of holding such a level of exigency album after album.

Verdict: 8. A record of great standing, confirming Enslaved in their status as a living institution of Nordic metal — one of those who have made longevity an art rather than a habit.