The Quatre motets sur des grégoriens, op. 10, by Maurice Duruflé (1902-1986) composed in 1960, are each based on the requisite Gregorian chant. In these motets Duruflé shows his genius for invoking the spiritual element of plainsong in a polyphonic context, achieving a suppleness of rhythm alongside strong characterization. Tu es Petrus, the shortest of the four motets, is a rousing and optimistic work. Here, the church's foundation on the rock of Peter isi ndicated by the building of the motet on its canonic opening to a strong and sturdy final cadence.

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