It was written in October – November 1975 during his final illness: the first four movements at his home, The Red House, Aldeburgh, and the fifth during his last visit to Venice, at Hotel Danieli.

Musicologist Peter Evans:"The profound impression it made then [at the premiere performance by the Amadeus Quartet] might appear an inevitable consequence of the occasion, but greater familiarity with the work confirms that the simplicity of its language and the serenity to which it aspires represent a distillation, not a dilution, of Britten's expressivity during the most poignant period of his life.

3 played at Tanglewood when I was teaching there in 1986, and it was a moving experience to witness a tough American modern music audience, nine hundred or a thousand of them, stunned into silence at the end, before they felt able to applaud.

"[2] Composer David Matthews:"The two earlier quartets had been among his finest instrumental works; the Third is their equal in invention, and in range and depth of expression their superior.

"[4] Musicologist Roger Parker:"This is, after all, a work that gestures again and again towards some of life’s great mysteries, its most humbling challenges; the steps one takes towards understanding it should, perhaps above all, be wandering and slow, ever aware of the subjunctive and the finite.