Guillaume de Machaut (1300-1377) wrote the earliest complete polyphonic setting of the mass to survive, the Messe de Nostre Dame. (Polyphonic: multiple voices, singing different melodic lines). In it, he employed a technique called isorhythm. Buried in the musical texture are the notes (but not the rhythm) of a pre-existing plainchant melody. The pitches of the melody are assigned to a repeating rhythmic pattern of the composer's invention. This is generally slow-moving. Over the top of this, higher voices sing ornate lines, more densely packed with notes. The plainchant tune is not easy to hear. As someone once half-flippantly put it, the music was so complex that "only God could understand it." There was no need for the listeners to understand what was going on, any more than they needed to understand the latin! Below is clip of the Agnus Dei from Mass:
This preoccupation with complexity -sometimes in fashion, sometimes out- has been a strand running through Western music ever since. Roughly speaking, it fell out of favour after the Bach era, but fell in again in the 20th century, partly inspired by our growing appreciation of the complexities of the world exposed by science. I'm speculating here, but it seems to me that Machaut's complexity grew out of the preoccupations of his own age and -although it's nigh-on impossible to think 14th century thoughts with a 20th century mind- it's difficult not to draw parallels.
Machaut was a contemporary of Julian of Norwich, who famously wrote:
"Also in this He shewed a littil thing, the quantitye of an hesil nutt [hazel nut] in the palme of my hand; and it was round as a balle. I lokid there upon with eye of my understondyng and thowte, What may this be? And it was generally answered thus: It is all that is made"This is a startling thing to read, especially to someone living today: it sounds almost like the sort of speculation a modern cosmologist might come up with. I'm not suggesting anything out of the ordinary or supernatural here. As I suggested, it would be foolish to pretend that one can understand the 14th century mind, but it's perhaps not surprising that her intuition should lead her to think like that. Physicists today often talk about the importance of intuition in what they do, even if they don't call it "the eye of their understanding".
The Shewings of Julian of Norwich (1373) (lines 148-51).