Paul VI was the Pope who radically changed basically everything after the close of the Second Vatican Council.
Most importantly in 1969, he promulgated his new mass, the Mass of Paul VI, also known as the Novus Ordo Missae (Latin for "New Order of the Mass"; often simply the Novus Ordo) and the Ordinary Form of the Roman Rite. The form of Mass in the Roman Rite during the preceding four centuries, 1570 to 1969, is called the Tridentine Mass (including the 1962 version which is now called theextraordinary form of the Roman Rite), while the various forms that succeeded each other in previous centuries are referred to as Pre-Tridentine Mass.
From the start, Paul VI's rite was intended to have an ecumenical nature as declared by its chief architect, Fr. Annibale Bugnini, a well known Mason, in 1965: '' We must strip from our Catholic prayers and from the Catholic liturgy everything which can be the shadow of a stumbling block for our separated brethren—that is, for the Protestants.”
Judging the Novus Ordo Missae in itself and in its official Latin form (printed in 1969), Cardinals Ottaviani and Bacci wrote to Pope Paul VI:
'' ...the Novus Ordo represents, both as a whole and in its details, a striking departure from the Catholic theology of the Mass as it was formulated in Session XXIII of the Council of Trent." (A Brief Critical Study of the Novus Ordo Missae, September 25, 1969). Paul VI Mass is the ordinary rite of the Mass throughout the world from 1969 till today.
Paul VI died on 6 August 1978.