In 1886 Parry was commissioned by Charles VIlliers Stanford to compose a piece for the Bach Choir of London, of which Parry was a member. Stanford, one of the first British musicians to recognize Parry's talent, called him the greatest English composer since Purcell. Asked to write a new piece, Parry turned, at the suggestion of his colleague George Grove, to Milton's ode "At a solemn musick" which he had been considering setting for many years.
Reviewing the concert, The Times said of Blest Pair of Sirens: The choral writing is in eight parts and abounds in contrapuntal devices. At the same time the spirit and the accent of the words are carefully attended to, as befits a work in which "sphere-born harmonious sisters, voice and verse" are invoked to "wed their divine sounds, and mix'd power employ". An excellent rendering contributed to the brilliant success of the ode.
The work was an immediate success, and was quickly taken up by other choirs. The following year it was included in the Three Choirs Festival. Recognised as "one of the outstanding English choral works", it has remained a standard in the choral repertory.
This edition has been prepared from the first published score. Besides being much clearer than the original, certain mistakes and anomalies have also been corrected.