The origins of codex Turin, Biblioteca Nazionale Universitaria J.II.9 are contested territory. While there can be little dispute that the repertory, a monumental collection of plainchant, polyphonic Mass settings, motets, and songs, is linked to the (Bourbon-)Lusignan court of Cyprus, this articles argues the north Italian origins of the manuscript. The key to solving the puzzle is the coat of arms prominently displayed on fol. 1r of the codex. Once its Brescian provenance is recognized and the relevant family's cultural, political, and religious history and patronage elucidated, the “Avogadro codex” emerges as part of a complex of “ars subtilior” sources including Chantilly, ModA, and Oxford 213, all now believed to have originated in Lombardy, Veneto, Romagna, perhaps Tuscany, or Rome, and either copied or still in use in the 1420–30s. The symbolic make-up of the manuscript reveals connections not only to the Avogadro but also to the cult of the Holy Cross in Brescia. Historical and paleographic evidence points to the possible involvement of Jean Hanelle, chapel master to the King of Cyprus, in the genesis of the manuscript around 1435. Hanelle may also have been responsible for taking the codex from Brescia to Savoy as early as 1436.