We’re hard at work putting together our next concert (May 6!), which features the incredible music of the Couperin family. One of the fascinating things about this period in France is the unmeasured prelude – improvisatory free pieces with no rhythm! Louis Couperin is sometimes actually credited with inventing this kind of piece, though actually there are several examples written for the lute that predate him, and probably other keyboard players were used to the idea of improvising similar preludes. He definitely was the first to write down versions for harpsichord that we know about though!
As an example, here’s the beginning of a d-minor prelude by Louis Couperin that I’ll be playing in the concert:

Even if you don’t read much music, you can see that all the notes look the same – no rhythm at all!
So how do you actually play something like this? It would be awfully dull (and incoherent!) to just go through playing each written whole note equally! Instead, we have to group the notes together into chords, scales, and make music out of them! The long slurs give some hints, showing which notes should be held together, and when they can be released, but there is still a lot that’s left to the personal taste of the performer. You can hear the same piece 20 times, and hear 20 completely different performances – sometimes it’s hard to even recognize that it’s the same piece!
Here’s a quick recording I’ve made of the two lines above so you can hear what it turns into:
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(download mp3)
François Couperin wrote a set of preludes as well, which he included in his Art de toucher le clavecin. In this immensely important pedagogical work, he actually wrote out the ‘unmeasured’ preludes with fully-notated rhythms! But he stresses that this is just to help out beginners, and that the rhythms are not to be followed exactly. Just like speech, he says, music has its poetry and prose, and good harpsichordists should be able to express themselves in both!