It is 25 years since the foundation of the York early music festival - during which time period instruments have moved from the margins to the mainstream, and, in the words of festival director Delma Tomlin, "We have grown a little older and our hair a little shorter."
Well, not entirely. It takes years of dedicated patience to develop beards of the luxuriance sported by some members of Hesperion XXI. But this unparalleled Iberian group, led by the pioneering violist Jordi Savall, was among the founding fathers of the early music movement, so they are entitled to look a little grizzled.
The theme of this year's festival is the music of the Spanish baroque, of which Hesperion is arguably the world's most distinguished and knowledgeable advocate. The first half of their concert served as a reminder, however, of just how esoteric and obfuscating early music programmes can be, featuring a sequence of late medieval Iberian composers of staggering obscurity.
The music marks a three-way split between Christian, Judaic and Moorish influences, in which hypnotic, Sephardic drones buzz ethereally beneath urgent reportage songs announcing the state of affairs in Granada. However incomprehensible the significance of soprano Montserrat Figueras's honey-pure orations, the sheer dexterity of Savall's viol-playing is mesmerising.
But it was the second half of the programme, featuring the more popular and folk-influenced elements of the 17th-century golden age, that induced a response close to pandemonium among festival-goers. Here the members of the ensemble, not least the baroque guitarist Rolf Lislevand, seized the chance - so far as period instrument practice permits of the term - to rock out. Jose Marin's Pasacalle: Mi Senora Mariantanos is only several evolutionary steps short of jazz, while his No Piense Menguilla Ya ("Don't Flatter Yourself, Menguilla") is Ritchie Valens's La Bamba by another name.
They concluded with an example of the 400-year-old Catalan folk-song repertoire that the group has begun to transcribe. One can only hope Hesperion's own legacy lasts twice as long.
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