Medieval to Modern – Jeremy Denk’s Wigmore Hall recital took us on a whistle-stop tour of Western music, beginning with Machaut in the mid-14th century and ending with Ligeti at the end of the 20th. The programme was made up of 25 short works, each by a different composer and arranged in broadly chronological order, resulting in a series of startling contrasts, but punctuated with equally surprising, and often very revealing, continuities.

It's not so long since Daniel Barenboim sat around a table with Israeli officials telling him that Wagner couldn't be played in the homeland when someone's mobile fanfared the "Ride of the Valkyries", demolishing the opposition's case. At the opposite end of the scale to all that flash of battle-lust came last night's unexpected first encore to a Wagner second half – the Act Three Prelude to Die Meistersinger von Nürnberg.

It's not often you think you detect a future Brünnhilde in a soprano performing a great Verdi role, but that was the case when American Tamara Wilson made her UK debut last autumn as a stunning Leonora in the ENO production of Verdi's The Force of Destiny. So would she sing the Ring? Not for 10 years at least, she said. But then Mark Wigglesworth, a conductor she knew she could trust as partner, proposed the final scene of Die Walküre at the Proms, and the rest should go down in history.

And so it ends: Hagen drowns, Valhalla burns, and the ring returns to the Rhine, while somewhere beneath – Wagner’s dawn trumpets sounding faintly in the distance – the dwarf Alberich continues his lonely scheming. It would be hard to find a more apt conclusion to a week of power-grabbing and back-stabbing than Götterdämmerung, and harder still to see its climactic conflagration as anything other than horribly prophetic. But where politics wreak chaos, so art must console, and this Ring cycle is consolation at its absolute purest and most ecstatic.

For some of us, Siegfried is a perfect opera. Like L.627 it stubbornly observes the Aristotelian rules of space and time to cut a generous slice of life. There are almost no set-pieces to break the flow of one-on-one conversations, accusations, confessions, arguments. These encounters are inevitably stifled by a concert staging, where singers address themselves to us, never to each other. Peter Mumford’s video projections set the scene with trees and glowing embers like a piece of slow TV on YouTube or BBC4.

Enter the human - and superhuman demands for at least four of the singers - in the second, towering instalment of Wagner's Ring cycle. It says so much for Opera North's achievement so far that no one fell in any way short of the sometimes insane vocal demands. There were only varying degrees of characterisation and commitment, none of them less than fine.

They promised Wagner for everybody at the Southbank Centre, and so far they're delivering. Community events cluster around a livescreening of each Ring instalment in the Clore Ballroom. We privileged few in the Festival Hall wondered how newcomers might be reacting out there, but there was no interval in the two-and-three-quarter-hour Das Rheingold to go and test the waters.

As the hand-held credits popped up on screen to pianist and musical director Manoj Kamps's superb quartet arrangement of Mozart's Magic Flute Overture, the European Union's Culture Programme logo brought a spontaneous burst of applause. Not the norm for Suffolk this week, I'm told, but this audience knew how international opera is, how we're all connected in Europe's musical world.

When I sang Isolde to Alberto’s Tristan at English National Opera all those years ago, it was a joy to hear such wonderful tenor sounds in my ears, my heart and my soul. It was always difficult for him to memorise his work and up until the first night I wasn’t quite sure what was going to happen. Yet when we went into that other place of performing he became Tristan and we travelled, on the waves of his beautiful sounds, to places I have seldom been.

"Bad Star Trek episodes" is how one director describes a certain unfortunate look in would-be intergalactic opera productions. The late Nikolaus Lehnhoff came perilously close to it in his Glyndebourne Tristan und Isolde but offered a coherent vision. Daniel Kramer, now ENO's Artistic Director, has a few "bad Star Trek episodes" and many good ideas that don't always join up or else outstay their welcome. Unevennness abounds: hideous costumes and makeup clash with Anish Kapoor's eventually brilliant designs, singing and conducting are only patchily inspired.