Even by the prodigious standards of Richard Wagner, there was a lot going on in his life as 1854 became 1855. For five years, since completing Lohengrin in the spring of 1848, he had composed no music, but the dam had finally burst. Work on the immense undertaking of the Ring had begun: Das Rheingold was complete, and Die Walküre sketched, though his private life was in turmoil. His wife Minna, for whom the phrase ‘long-suffering’ could have been coined, was his sole companion as a political exile in Zurich, and the relationship, though still with remnants of warmth, was falling apart. Then he came across a copy of Schopenhauer’s Die Welt als Wille und Vorstellung (The World as Will and Representation), which, despite its relentless pessimism, he hailed as a ‘gift from heaven in my loneliness’.

Schopenhauer’s chief idea in the work, the denial of the will to live, struck Wagner as one of ‘terrible seriousness’, but also an idea that offered ‘a unique means of redemption’. It became the inspiration for Tristan und Isolde, for many Wagner’s most complete, certainly his most musically radical, masterpiece. Wagner was familiar with the 13^th century telling by Gottfried von Strassburg of the medieval romance, probably Celtic in origin, though interest in the subject had been reignited by an acquaintance, Karl Ritter, who planned to dramatise it. His best friend, Franz Liszt, was enthused by the possibility of Wagner himself adapting the chivalric tale – ‘Dearest Richard,’ he wrote to Wagner, ‘your Tristan is a splendid idea; it could become a glorious work. Don’t abandon it!’

And he didn’t, though amid the completion of Die Walküre and part of Siegfried (the penultimate part of the Ring), Tristan was put on the back burner, until a muse arrived in the shape of the 23-year-old Mathilde Wesendonck, wife of Wagner’s latest in a long line of patrons, Otto von Wesendonck, a silk merchant who had retired to Zurich and in whose grounds Wagner resided. There has been much speculation about the nature of the romance between Richard and Mathilde, but it was profound enough to inspire the composer to create a song-cycle from Mathilde’s poetry – the Wesendonck Lieder – in which he unveiled the radical, ambiguous, chromatic sound world of constant yearning and love-drenched oblivion  – as well as that chord – which was to characterise Tristan.

The prelude of Tristan und Isolde, which still startles today, was met with puzzlement if not hostility when it was premiered in Paris in 1860. Berlioz, usually the most incisive critic among the great composers, described it as a ‘slow movement, without any other theme than a sort of chromatic sigh’. Eduard Hanslick, the doyen of Vienna’s music press, thought it a ‘boneless tonal mollusc’. But Wagner knew what he had achieved: ‘Tristan is and remains to me a miracle!’ he declared.

The completed opera was scheduled to open in Vienna in 1862, but was abandoned after 77 practice sessions. The situation looked hopeless; it had been years since a Wagner premiere. And then the young Ludwig II came to the throne of Bavaria, a relationship that was be no less of a romance, at least on the patron’s side, than that of Richard and Mathilde. On 10 June 1864, Tristan und Isolde was premiered in Munich, under the baton of Hans von Bulow – another of Wagner’s cuckolds, married to Liszt’s daughter Cosima, who would become Wagner’s second wife and problematic guardian of his legacy, having already borne him a daughter, Isolde (naturally).

It has maintained its place among the vanguard of supreme artistic creations ever since, and the current Glyndebourne Festival Opera production, a sensitive, luminous revival by Daniel Dooner of Nikolaus Lehnhoff’s original, does it sublime justice. Conductor Robin Ticciati – who we must now rank among the leading Wagnerians of his time – brings energy and pace to the score from the off – producing an intoxicating, buzzy, soundscape from the London Philharmonic Orchestra. The closing bars following the Liebestod, with woodwind spare but precise, is among the best I have heard. Isolde is the Finnish dramatic soprano Miina-Liisa Värelä, and a captivating one, understandably the object of Tristan’s ‘dangerous fascination’. Stuart Skelton in the other title role found it hard to navigate the set of vortex spirals – always a big man, the Australian heldentenor now appears quite vast and, in the first act, vocally underpowered. But his qualities of phrasing and vocal beauty re-emerged, especially in Act III. While the stars shone amid Roland Aeschlimann’s minimal powdery-blue set, with its welcome echoes of Wieland Wagner’s golden age productions at Bayreuth, so did the rest of the cast.

Marlene Lichtenburg, a last-minute replacement for Karen Cargill, inhabited with ease the role of Brangäne, dressed in a costume surely inspired by the statue of Princess Ute at Naumburg cathedral (which also inspired the Queen in Disney’s Snow White). Shenyang, a former Cardiff Singer of the World, was similarly authoritative as Tristan’s aide, Kurwenal, while Franz-Josef Selig, as the cuckolded King Marke – there’s a theme here – navigated the Act II monologue with gravitas and a kind of broken dignity – it is one part of the work that can drag.

Next year, Glyndebourne, a house long noted for its Mozart and Strauss productions, is staging Parsifal, Wagner’s final work, for the first time. One hopes for a similar clarity and simplicity to this Tristan. One thing we can be pretty certain of is that Ticciati and the LPO will rise to the occasion. This extraordinary performance is just another in a long line of fine Wagner productions staged in Britain in recent years – the Longborough Ring Cycle and the Opera North Parsifal being notable among them. If you want Wagner shorn of the increasingly absurd – and outdated – excesses of European regietheater, this side of the Channel provides a bountiful haven.

Tristan und Isolde is at Glyndebourne until 25 August.