I suppose this is as far back as we go, except in the unlikely event that someone can unearth Horncastle.

I'm beginning to think that an exhumation order could prove very interesting!

According to the website of St Patrick's Cathedral, Armagh there was evidence "that he became a little careless in his attitude to his duties [as organist]", and eventually he was sacked from his position there. But the Archbishop certainly dismissed him in high style by posting a notice at Horncastle's residence and at the Chapter Room door of the Cathedral:-
Therefore We, John George, Archbishop aforesaid and Visitor of said College of Vicars and Organist, on account of the turbulence, contention, insolence and contumacy of said Frederick William Homcastle do pronounce and decree that the said Frederick William Homcastle be removed from his said office of Organist and Master of the Choiristers and that the licence or Patent heretofore granted to him be revoked, cancelled and declared null and void, the peace and good order of said College of Vicars in said Cathedral so requiring.

I wonder what on earth could have provoked such a splendid addition to his CV as the above? I found in Groves Music Online that Horncastle wrote an article in the Quarterly Musical Magazine of 1822 accusing Handel of plagiarism. Was that really a sackable offence at the time?

Matthew Edwards