He was respected by Mozart, revered by Schubert, and regarded during his lifetime as the leading contemporary composer of church music.
Who was he? The answer is Michael - yes, Michael - Haydn.
Johann Michael Haydn, to give him his full name, has come down to posterity as little more than a footnote in the biography of his celebrated older brother, Joseph.
After all, Joseph Haydn was 'father' of the symphony and the string quartet - and Michael wasn't.
Michael Haydn may be less historically significant than Joseph, but he's nonetheless an important composer in his own right, and his achievement has been overshadowed in a way that it might perhaps not have been had he borne a different family name.
Michael Haydn has come down to posterity as little more than a footnote in the biography of his celebrated older brother, Joseph.
Donald Macleod takes him out of those footnotes and into the footlights, placing him centre-stage for a change - a position he can occupy quite unapologetically and without having to ask his big brother's permission.
This episode sees him take up his first job - as Music Director to the Bishop of Grosswardein - and move on to his second, as concertmaster to the archiepiscopal court at Salzburg, where he was to remain until his death 43 years later, working alongside Leopold Mozart and, for a time, his son Wolfgang.
On the playlist: Haydn's first symphony; an early liturgical work, Christus factus est; his only surviving piano composition; and an extract from one of his most brilliantly virtuosic serenades.
Donald Macleod on Michael Haydn's time as music director to the Bishop of Grosswardein.
Donald Macleod explores two Michael Haydn works of markedly different character, beginning with the Concertino for Horn, which showcased the talents of one of the virtuoso players at Haydn's disposal in the archiepiscopal court at Salzburg.
This contrasts with his Requiem for Archbishop Sigismund, a dark and brooding piece written to commemorate the passing of his late, lamented employer, but informed too by the composer's grief at the death of his only child.
This is one of the works that established Haydn's reputation as a composer of liturgical music - and one which Mozart took as a model for his own Requiem.
Horn Concertino in D, MH134 (excerpts)
Barry Tuckwell (horn)
Academy of St Martin in the Fields
Neville Marriner (conductor)
Decca 475 7463 - CD1, Trs 8-9
Requiem pro defuncto Archiepiscopo Sigismundo, MH 154
Carolyn Sampson (soprano)
Hilary Summers (contralto)
James Gilchrist (tenor)
Peter Harvey (baritone)
Choir of the King's Consort
The King's Consort
Robert King (conductor)
Hyperion CDA67510 - CD 1, Trs 1-9.
Donald Macleod explores Haydn's Concertino for Horn and Requiem for Archbishop Sigismund.
An examination of Michael Haydn's Missa Sancti Hieronymi, written to mark the 10th anniversary of the accession of his boss, Hieronymus Colloredo, to the archbishopric of Salzburg.
It quickly became known as the 'Oboe Mass', on account of its highly unusual use of six oboes.
Leopold Mozart was critical of what he regarded as Haydn's heavy drinking, but lavish in his praise of this impressive work, whose first performance he attended.
The programme concludes with Haydn's Symphony in G, which until recently was thought to be by Wolfgang Mozart.
composed 20 symphonies during the 1780s, but his Symphony in A major, written in 1789, was to be his last.
Perhaps he decided he had nothing further to contribute to a genre which already included Mozart's 'Jupiter', composed the previous year.
Or perhaps he was simply kept too busy writing church music.
Towards the end of 1800, Haydn's cosy and somewhat uneventful life was rudely interrupted by history - Napoleon's forces occupied Salzburg, and his apartment was looted.
He was robbed of two silver watches and a month's wages, and the following year he travelled to Vienna in search of new income.
One result was a commission from Empress Maria Theresa.
Another was the offer of the position of Kapellmeister at Eisenstadt, taking over the reins from his brother Joseph - to his subsequent regret, he turned it down.
The story of Michael Haydn closes with another Maria Theresa commission - the Missa sub Titulo Sti.
Leopoldi, written for the Feast of the Holy Innocents on 28 December 1805 and appropriately featuring boys voices.
It's a charming work and a fitting conclusion to half a century of extraordinary musical productivity.
Donald Macleod explores music from Haydn's last two decades, including his last symphony.