This spurious work was premiered on 1 December 1894 at the Crystal Palace, London. The following anecdote is related by Stephen De'ak on pages 219-220 of his book:

In the early eighteen-nineties, during the intermission of one of Popper's Vienna recitals, Popper received an interesting windfall. A man who appeared at the artist's room handed Popper a few sheets of wrinkled manuscript papers, saying that they were some sketches for a cello concerto, by Haydn, that perhaps Popper would find the material interesting, and that he was welcome to have it. Popper was slightly skeptical but thanked him, commented that he would see what he could do with it. The source of the papers and identity of the gentleman are complete mysteries. A few years later, during summer vacation, Popper took time to study the almost forgotten sketches and judged that the themes were genuinely by Haydn. Thereupon, he set out to work them into a concert form of three movements, for which an outline had already been provided. Popper wrote the piano accompaniment and orchestration. The result was the Haydn C major Cello Concerto, published in 1899 by Ries and Erler, in Berlin. According to inquiries, no one knows the whereabouts of the original sketches today. For two years Popper had not toured in middle Germany, when in December 1899, he played there in several towns — among them Braunschweig and Halle. The critic correspondent enthusiastically reports these concerts: "Popper's heavenly playing brought stormy acclaim from the audience. In addition to his own compositions, he also performed beautifully Haydn sketches which he recently discovered and has arranged into a Haydn C major Concerto; from every point of view, the three movements show the good old Haydn at his best.

The following comes from The Musical Times and Singing Class Circular Vol. 36, No. 623 (Jan. 1, 1895), pp. 23-24: 

 The Concerto in C for violoncello and orchestra, introduced by Herr Popper at the Concert of the 1st ult. is attributed by that eminent virtuoso to Haydn. Unfortunately, the evidence adduced is inconclusive. The score was given to him by an old amateur in Vienna some twenty years ago, but it has not transpired whether the manuscript affords any clue to the identity of the author. As no traces of the accompaniment could be discovered at Esterhaz or elsewhere, Herr Popper has himself scored the work for an orchestra of the usual dimensions of Haydn’s Concertos, and acquitted himself of the task with conspicuous skill and discretion. The Concerto, which is in three movements [...] is of a decidedly pleasing character, and, if not written by Haydn, is certainly thoroughly Haydnesque both in form and spirit.

It is difficult to believe that someone would take this work to sound like genuine Joseph Haydn, based on authentic sketches or spurious ones. At the dawn of the age of musical forgeries, it is safe to assume that the sketch that was handed to Popper was, too, spurious until scholarship demonstrates otherwise. However, as a genuine work by Popper, this concerto reflects well his interest in the neo-classical style.

1. Allegro moderato
2. Andante
3. Allegretto vivace  

First Edition: Ries & Erler: vc/pf plate 6821