There's far more to minimalism in music than Glass, Reich and Riley. Significantly there is Arvo Part, whose particular avenue of classical minimalism is the ideal of 'sacred music'.
Part had a dramatic split in his career as a composer when he moved away from Schoenberg's twelve tone technique and its attendant serialism . The Estonian composer closed out that aspect of his oeuvre and entered a period of contemplative silence.
As Part's biographer, Paul Hiller observed, "He had reached a position of complete despair in which the composition of music appeared to be the most futile of gestures, and he lacked the musical faith and will-power to write even a single note".
By studying the early roots of Western music, Part essentially rediscovered his faith in the art-form by channeling plainsong, Gregorian chant and early Renaissance polyphony.
The result is a body of work that is liturgical and deeply spiritual.
As his contemporary Steve Reich states," I love his music, and I love the fact that he is such a brave, talented man .... He's completely out of step with the zeitgeist and yet he's enormously popular, which is so inspiring. His music fulfills a deep human need that has nothing to do with fashion"