Zimmermann once characterised himself as being ''a mixture of monk and Dionysos from the banks of the Rhine''. Large-scale, explosive works of all genres are balanced by an almost ascetic reticence. The second section of the collection of piano pieces entitled Enchiridion was composed in 1952 and is subtitled Exertizien [spiritual exercises]. The movement headings Vigil, Hora and Matutin make reference to the monastic Liturgy of the Hours, although Zimmermann specifically refers to the function of the cycle as ''studies in expressive playing and touch''. Throughout his life, Zimmermann remained a religious individual shaped by Catholicism. He inscribed many of his later works with the abbreviation O.A.M.D.G., the Jesuit motto ''Omnia ad maiorem Dei gloriam'' [All for the greater glory of God].