What if one of the most famously guarded pieces of music in history was never really locked in a vault, and the soaring high note that gives listeners goosebumps today was the product of a documented clerical error? This episode traces the strange biography of Gregorio Allegri's Miserere mei Deus, composed in the 1630s for the candle-extinguishing Tenebrae services in the Sistine Chapel, drawing on Leopold Mozart's 1770 letters, Charles Burney's travel diaries, the 1661 Sistine Codex and Robert Haas's 1932 edition.

We dismantle the legend that a 14-year-old Mozart transcribed the piece from memory after a single hearing, noting that the Academy of Ancient Music in London was already performing it in the 1760s and that Mozart had just visited Padre Martini, who owned an authorized copy. The real secret was never the sheet music but the abbel ...