Schoenberg and co begat Boulez and co, but where were the successors to Bartok and Janacek? Incinerated in Auschwitz in 1944: Hans Krasa, Viktor Ullmann and Pavel Haas were the pre-eminent voices of Czech music in the Twenties and Thirties, and their disappearance left a gaping void in musical history.
Haas's String Quartet No 2, composed 10 years before he was swept up into the Nazi nightmare, has the dreaminess of Janacek and the pared-down, angular beauty of Bartok, and it stands as an ineffably sad monument to the greater music he might have gone on to write.
To hear it played in St Andrew Holborn Church by the Pavel Haas Quartet, with its recently rediscovered percussion part added by percussionist Colin Currie, was a rare privilege; Haas's evocation of country sounds and the rhythms of village life was beautifully rendered.
But the audience that packed this concert had primarily come to hear Peter Maxwell Davies' reworking of a Thomas Tomkins piece, A Sad Paven for these Distracted Tymes, and to celebrate the premiere of a work by Alexander Goehr. The Sad Paven was a powerful and densely worked miniature, which began with bleached viol textures and then did a Bartok on them.
Goehr's piece was gnomically entitled Since Brass, nor Stone... Fantasia for string quartet and percussion Op 80, and seemed at first an odd melding, with the percussion going one way, while the strings went their own darker way. Yet this apparent dislocation actually cohered: ending interrogatively mid-phrase, it had an introverted, gritty beauty.
On then to the cloistered medieval calm of Charterhouse, where original things were going on, courtesy of the Counterpoise ensemble. In the hands of Alexandra Wood (violin), Kyle Horch (saxophone), Deborah Calland (trumpet), and Helen Reid (organ), Wagner's Siegfried Idyll made distilled sense, and, with Eleanor Bron joining the group as narrator, the Gothic melodramas that followed had an odd piquancy. But their pièce de résistance defied categorisation: with its accompanying text and video, Edward Rushton's On the Edge did weird and wonderful things with avalanches and death in the snow.
The City of London Festival runs to 24 August (www.colf.org)