Fratres was one of the first pieces Estonian Arvo Pärt wrote in his radically new style “tintinnabuli”. His early compositions, following Shostakovich and Prokofiev, had been neo-classical in style. They included film and theatre music, and were favored with the Soviet cultural authorities. He subsequently studied the few ‘serialist’ scores that leaked inside the iron curtain, leading to the composition of Credo in 1968 in which the famous Bach C major prelude is gradually distorted by 12-note row techniques before returning to tonality. It was condemned by the authorities, more for its assertion of Christianity, than for its invocation of Schoenberg.

There followed seven years of minimal creative output, when Pärt explored monody and simple two-part counterpoint inspired by his studies of medieval and renaissance music and Gregorian chant. Eventually, in 1976 a new style had emerged which he called ‘tintinnabuli’ after the bell-like sound of the notes of a triad. The technique involves two voices: melodic, moving stepwise around a central pitch, and a tintinnabuli voice sounding the notes of the tonic triad. The relationship between the two voices follows a predetermined numeric or prosodic scheme and is certainly not, as one would indeed expect from a student of Schoenberg’s work, haphazard. Pärt's subsequent work has broadly continued in this style; dubbed 'holy minimalism' along with the related work of Górecki and Tavener, it has proved immensely popular.

Fratres (Brethren) consists of a theme and eight variations. The theme is a very constrained six-bar phrase (illustrated); its first three bars have 7, 9 & 11 beats respectively, with two extra notes being added to the middle of the previous bar. The simple, chant-like melody is played in parallel tenths by the upper and lower notes of each chord, while the middle note comes from an A-minor chord (A,C,E). In the second three bars, the melody in the upper and lower notes is inverted and a different A-minor note is chosen for the middle. In subsequent variations, the central pitch of the theme (initially C#) descends.

The original 1977 composition left the instrumentation open, but Pärt produced a version specifically for violin and piano in 1980 which he dedicated to Gidon Kremer and his wife. The variations explore in turn different technical possibilities of the violin.

Edgar Alan Poe perhaps anticipated Pärt's style in his well-known 1831 poem "The Bells":

Keeping time, time, time,
In a sort of Runic rhyme,
To the tintinnabulation that so musically wells 
From the bells, bells, bells, bells…

Spiegel Im Spiegel (1978) for Violin and Piano

Originally for violin and piano, Spiegel im Spiegel (German for mirror in the mirror, referring to the infinite number of reflections two mirrors can create) has been performed with a number of alternative melodic instruments. It sits, calmly, in the key of F major, outlined by the ever-moving ascending three-note piano arpeggio figures, reminiscent of the first movement of Beethoven’s Moonlight Sonata, while the violin explores single notes. The result is haunting, beautiful, sonorous and calming. Introduction of this work cemented Pärt's reputation as one of the world's leading living composers.