Quo Primum Tempore (English: From the beginning whence) is the incipit of an Apostolic Constitution in the form of a Papal bull issued by Pope Pius V on 14 July 1570. This Pontifical decree promulgated the Roman Missal and made its use obligatory throughout the Latin Church of the Catholic Church, except where there existed a different Catholic Mass liturgy of the Latin Church of at least two hundred years prior and standing.