Myer Lyon, better known by his stage name Michael Leoni, was a hazzan at the Great Synagogue of London who achieved fame as a tenor opera singer in London and Dublin, and as the mentor of the singer John Braham.

The Great Synagogue of London was a former Orthodox Jewish congregation and synagogue, located in the City of London, England, in the United Kingdom. The synagogue was, for centuries, the centre of Ashkenazi life in London. Built north of Aldgate in the 17th century, it was destroyed during World War II, in the Blitz.