Its single movement is based on the parable of the Good Samaritan with a Latin text by Patrick Wilkinson, and was composed for the centenary of the Red Cross.

[1] To resolve this issue, Britten approached Wilkinson, a Latin professor at Cambridge University, to create a libretto for the work.

The resulting text is "somewhat 'academic' and lacking in obviously expressive poetic qualities" but is notable for its "recondite, elegant, Classical Latin diction".

[4] The work is in a single movement with "a highly unified structure built up out of short interlinked sections".

[3] Eric Roseberry describes this piece as "yet another minor masterpiece in which once more [Britten's] skill and science as a composer objectify his unique poetic sensibility".