A sacred choral piece, usually unaccompanied, in several parts – that’s about as close as one can get to a definition of ‘motet’ without excluding whole swathes of repertoire.
But as with that other hugely important European musical form, the symphony, the motet’s formal fluidity is a sign not of inherent vagueness, but of strength and health – the ability to survive and thrive in times of huge cultural shifts.
In essence, the medieval motet represents the first great flowering of that distinctly Western innovation, polyphony. The term ‘motet’ appears to derive from the French ‘mots’ – ‘words’ – though the jury is still out on that.
It is, however, in that very profusion of texts, sung simultaneously to dynamically contrasting vocal lines, that the motet emerged as a medium for complex virtuosic composition.
A Latin plainchant, generally sung in relatively slow notes, provided the basis – the ‘cantus firmus’ – around which composers like the biographically shadowy Pérotin (c1200), and later Machaut, Dunstaple and Dufay, wove faster-flowing lines setting words that relate to the chant’s main ideas or images.
Mind you, the relation could be pretty tangential. The extra texts might be in another language, or a motet in praise of the Blessed Virgin might also include words from a contemporary pop song, possibly hymning female attributes a long way removed from virginal purity.
Even so, there seems to have been an assumption, confirmed by theorists like Johannes de Grocheo, that the motet was a form for connoisseurs, and definitely not for ‘the vulgar’.
Take those last two characteristics together and you can understand the Church’s attempts to rein composers in – as famously at the Council of Trent (1545-63).
If the medieval motet was still hierarchical (cantus firmus firmly at the centre) the motet that emerged from it and flowered during the Renaissance and baroque periods was more egalitarian – ‘humanist’ you might even say.
Motifs were shared between the parts, so that each voice has a taste of what it is to be ‘first among equals’. In the hands of such masters as Palestrina, Victoria and Byrd, motets could convey an impressive range of ideas and feelings, from sublime, luminous order to intense, even painful emotions.
Since then, great things have been added by Schütz, Bach, Mozart, Brahms, Bruckner, Poulenc and Messiaen, but few would argue that these surpass the masterpieces of the late Renaissance.
This article was first published in the October 2014 issue of BBC Music Magazine