 In his "De Servorum Dei beatificatione et de Beatorum canonizatione" of five volumes the eminent canonist Prospero Lambertini (1675–1758), who later became Pope Benedict XIV, elaborated on the procedural norms of Pope Urban VIII's Apostolic letter "Caelestis Hierusalem cives" of 1634 and "Decreta servanda in beatificatione et canonizatione Sanctorum" of 1642, and on the conventional practice of the time.His work published from 1734 to 1738 governed the proceedings until 1917.The article "Beatification and canonization process in 1914" describes the procedures followed until the promulgation of the "Codex" of 1917.