Collage (from the French: coller, "to glue") is a technique primarily used in 20th century visual arts, where different materials are used in one artwork. In music, collage usually means the playful usage of contrasting musical material of different periods and styles of music history, as well as combining fragments of the works by different composers for creating a new piece.

Arvo Pärt´s musical pieces composed in collage technique are the most remarkable part of his early period works. In his Collage über B-A-C-H, cello concerto Pro et contra (1966), Symphony No. 2 (1966) and Credo (1968), two musical but also spiritual worlds have been set against each other. He describes those worlds as if separated by a deep abyss, which, at the same time, he longs to transcend. Pärt’s dodecaphony here represents the “unbearable atmosphere of barbed wire” (to use his own words) of all modernist music, and the quest for beauty, purity and perfection is expressed through the stylization of Baroque music (Pro et contra) or concrete quotes primarily from Bach (Collage über B-A-C-H, Credo), but also Tchaikovsky (Symphony No. 2), for example. Those works are witness to the growing inner anxiety and crisis for the composer. The most extreme and dramatic of them is Credo, composed in 1968 – it is the final renunciation of all means of musical expression so far, the turning point in his oeuvre as well as his life.

In Arvo Pärt´s music the collages are like a bridge between his early and late compositions:

One can see collages as a mixture of positiive and negatiive, true and false. These are a sort of transplantation: if you have the feeling that you don’t have a skin of your own, you try to take strips of skin from all around you and apply them to yourself. In time these strips change, and turn into a new skin."

 (Enzo Restagno, Arvo Pärt in Conversation, 2012, p. 17)