Ton Koopman/Tini Mathot, Wigmore Hall, London

It may be thirty years since ‘early music’ escaped from its ghetto, but we are still finding fresh worlds within it.

Ton Koopman and Tini Mathot - who have consummated their pupil-teacher relationship in a marriage both on and away from the keyboard - concluded their Wigmore residency by giving us a tour d’horizon of one of these: music for four hands on a variety of instruments. Composers in Bach’s day filled their houses with harpsichords, spinets, and clavichords: the Bach Prelude and Fugue BWV547 with which they opened their recital showed what a wonderfully intricate edifice two big harpsichords could conjure up.

Then Dietrich Buxtehude’s music came centre-stage, in the form of a prelude whose showy brilliance demonstrated exactly why Bach and Handel both made pilgrimages to Lubeck to hear this great organist improvise. Koopman - with the air of a quizzical Dr Freud - was alone at the controls for this one, flipping the stops and luxuriating in the sound-worlds he could create. Next, Mathot played Couperin’s ‘L’Imperiale’, a suite of fifteen short character-pieces which were originally designed to reconcile eighteenth-century French and Italian styles, but which for us reflect this French composer’s inexhaustibly colourful invention. Koopman followed with CPE Bach’s extraordinary ‘F sharp major Fantasia’, which began with an echo of one of his father JS Bach’s most plangent preludes, but then wandered into realms of skewed chromaticism which really belonged far in the future.

From this point on, the pair sprung surprise after surprise. Mozart found some strange ways to express his devotion to Bach and Handel, but none stranger than the two pieces which were played here - a Fantasia and an Andante for automated organ, with the Koopmans’ playful rubato underlining Mozart’s impatient attitude to his instrument. A Handel piece also came out of the blue, in the form of a two-keyboard suite of which just one part survives, with the other being reconstructed by Ton Koopman. It was a pleasure to encounter the music of Juan Bautista Jose Cabanilles and Pablo Bruna - both from the Spanish Baroque - and to hear the sumptuous concerto by Wilhelm Friedemann Bach which in the nineteenth century was attributed (understandably, given its excellence) to his father, the great JS. In short, a feast.