The gestation of this titanic work, now a pillar of the concerto repertoire, was exceptionally long and tortuous. Brahms was first and foremost a pianist, and when he first visited Schumann in 1853 it was with two huge sonatas completed and the third in his head. Already that same year he started work on a D minor sonata for two pianos, but a crucial inspiration for the stormy first movement was the traumatic events of early 1854, when Schumann attempted suicide by throwing himself into the Rhine, was hauled out raving, and taken to an asylum. By spring that year, when still a young man not yet 21, Brahms had completed three movements which he played through with Clara Schumann. But he wrote to Joachim: “…to tell the truth, not even two pianos are enough for me”, and he tried to rework the first movement as the opening of a symphony, but virtuoso piano writing kept intruding into the texture.

The initial inspiration for making the piece into a piano concerto came in a dream which Brahms related to Clara in January 1855: “Just listen, what I dreamt last night: I had transformed my poor wretched symphony into a piano concerto, and was playing it all, a first movement, then a scherzo and a huge and terribly difficult finale – I was quite inspired.” The slow scherzo eventually reappeared as the second movement of the Requiem, and the finale was doubtless replaced completely, but the essential concept was there. The Adagio was probably composed at the very beginning of 1857, both an affectionate portrait of Clara and a reverent tribute to Robert Schumann who had died so tragically the previous July; between the two piano staves in the autograph score Brahms wrote – in ink, as if belonging definitively to the score – (Benedictus, qui venit, in nomine domini!), and the extent to which these fit exactly to the opening melody is most poignant.

But he remained dissatisfied, repeatedly asking for Joachim's advice, and even after the first performance, which he gave in Hanover on 22 January 1859 with Joachim conducting, he was still revising the first movement “which refuses to be born”.