The Hilliard Ensemble first encountered the Codex Speciálník when researching music for their album of Walter Frye (ECM 1476), whose Ave Regina appears in the manuscript with an extra part, presumably added by a local Czech composer. The Codex is one of the oldest surviving collections of Czech renaissance polyphony, and originated in the Utraquist protestant congregations of around 1500. The related Strahov Codex is some 10 to 15 years older, but was used by the Catholics and may have come from Moravia or Silesia. If 1500 seems rather late for renaissance music to have reached Prague, it should be remembered that the Hussite Wars of 1419–1434 had divided the ‘nation of heretics’ from the rest of Catholic Europe, and it was only in the last quarter of the 15th century that there was a significant inflow of cultural and artistic ideas. The Codex Speciálník was not the first collection of renaissance polyphony: many of its pieces had clearly been in circulation for some time.