The first Mass was said by Christ at the Last Supper (Mt. 26:26-29, Mk. 14:22-24, Lk. 22:19-20, 1 Cor. 11:23-29). At that Mass, Christ told the Apostles - the predecessors of today's bishops - to repeat his actions in commemoration of his death. Since that time, the Church has faithfully followed the Lord's instructions, celebrating Mass even during the height of persecutions.
Under the direction of the Holy Spirit, the Roman Mass naturally developed, and the established customs became "ritualized" over the centuries. The 'legalization' of Christianity furthered the process, and it became possible to have more elaborate ceremonies which better emphasized the dignity of what occurs in Mass. Such additions were considered natural developments since the Church went from being "illegal" and underground (necessitating its Masses to be "brief and simple") to legal, and even protected. Although various additions were made, this gradual development was natural, organic, and respected the previous traditions.
As early as the fourth century, fixed liturgical rites can be found in the Church. And, in fact, we can see that the core of the Canon of the Traditional Mass (as it appeared before the Second Vatican Council) existed at least since the end of the fourth century. These fixed rites made it possible for persons to easily remember what was necessary, and they protected the liturgy from error. Although there were a number of legitimate rites in the early Church, each rite had various points of congruence, and it is believed that the most important points of the ancient rites could be traced to Apostolic times.
The Roman Missal was reformed during the pontificate of Pope St. Gregory the Great (590-604 A.D.), but his reforms were faithful to Tradition. His work remained virtually unchanged until the Second Vatican Council. As stated by one liturgical scholar: "From roughly the time of [Pope] St. Gregory [the Great, d. 604] we have the text of the Mass, its order and arrangement, as a sacred tradition that no one has ventured to touch except in unimportant details." (Fortescue, 1912 A.D.)
Eventually, the Roman Rite spread throughout the West and became predominant. Note that it is a common error to assume that the Eastern liturgies are older than the Roman liturgy. As stated by Davies: "[T]here is no existing Eastern liturgy with a history of continual use stretching back as far as that of the Roman Mass."
In fact, the central elements of the Roman Rite remained virtually untouched until the Protestant 'Reformers' instituted drastic changes to the Mass in the 16th century. Their changes were designed to destroy the faith of Catholics. They even dared to touch the Canon of the Mass, and they removed all references to sacrifice and other elements that contradicted their false theology. Never before had anyone dared a major reform of the liturgy.
The Church, however, the ever-watchful Pope St. Pius Vguardian of the liturgy, protected the Mass by codifying the so-called 'Tridentine' Rite, which was promulgated by Pope St. Pius V, the last sainted pope until Pope Pius X in the 20th century. This Rite was not a new rite of Mass, but rather the codification of the existing Roman Rite, which could be traced back, in all essential elements, even to apostolic times.
"The Order of Mass as found in the 1570 Missal of St. Pius V (1566-1572), apart from minor additions and amplifications, corresponds very closely with the Order established by St. Gregory (d. 604 A.D.)." (Davies)
"All later modifications were fitted into the old arrangement, and the most important parts were not touched. From, roughly, the time of St. Gregory we have the text of the Mass, its order and arrangement, as a sacred tradition that no one has ventured to touch except in unimportant details [until the Second Vatican Council]." (Fortescue)
"Essentially, the Missal of Pius V is the Gregorian Sacramentary; that again is formed from the Gelasian book, which depends on the Leonine collection. We find the prayers of our Canon in the treatise De Sacramentis [of St. Ambrose, c. 340-397] and allusions to it in the IVth century. So our Mass goes back, without essential change, to the age when it first developed out of the oldest liturgy of all." (Fortescue)
This formal promulgation of the 'Tridentine' Mass served to protect the liturgy from error, and protected it from those outside the Church who sought to destroy the Mass. The promulgation of the 'Tridentine' Rite in the 16th century was the first time in history that the liturgy was legislated - as it were "canonized". With the codification of the 'Tridentine' Rite and the invention of the printing press, it was possible to have liturgical standardization throughout the world, wherever it was used. As stated by Pope St. Pius V:
"[I]t is most becoming that there be in the Church only one appropriate manner of reciting the Psalms and only one rite for the celebration of Mass"
From the time of its formal codification, the canon of the Mass was generally considered virtually "untouchable" until the Second Vatican Council. As stated by Davies:
"One cannot emphasize enough that St. Pius V did not promulgate a new Order of Mass (Novus Ordo Missae). The very idea of composing a new order of Mass was and is totally alien to the whole Catholic ethos, both in the East and in the West. The Catholic tradition has been to hold fast to what has been handed down and to look upon any novelty with the utmost suspicion. The essence of the reform of St. Pius V was, like that of St. Gregory the Great, respect for tradition." (emphasis added)
He also states:
"[T]he unbroken tradition of East and West for over 1,600 years, that the Eucharistic Liturgy should never be subjected to radical reform - although it might develop through the addition of new prayers and ceremonies - was breached in 1970 when the newly composed Missal of Pope Paul VI was published, the New Order of Mass having been published in 1969." (Davies)
Unlike Pope St. Pius V's 16th century reform which consisted of a codification of an existing rite and was faithful to tradition, Pope Paul's 1960's Novus Ordo Missae (Novus Ordo Mass) was fabricated by a committee (with the assistance of Protestant 'observers') and constitutes an unprecedented, and radical, break with tradition. The revolutionary nature of the changes incorporated in the New Rite of Mass are striking, and as Cardinals Ottaviani and Bacci stated:
"[T]he Novus Ordo Missae - considering the new elements, susceptible of widely differing evaluation, which appear to be implied or taken for granted - represents, as a whole and in detail, a striking departure from the Catholic theology of the Holy Mass as it was formulated in Session XXII of the Council of Trent, which, by fixing definitively the 'canons' of the rite, erected an insurmountable barrier against any heresy which might attack the integrity of the Mystery."
It is clear that there are many differences between the New Rite of Mass and the 'Tridentine' Rite of Mass. Note: Click here for more information on this topic. Further, in the decades since its imposition on the faithful, the New Rite of Mass been plagued by numerous troubles - including liturgical abuse, sacrilege, doctrinal confusion, loss of faith, reduced Mass attendance, loss of the sense of the sacred, loss of fear of the Lord, loss of belief in the Real Presence, blurring of the distinction between the priest and laity, etc.
Thankfully, however, the glorious 'Tridentine' Mass has been protected from such misfortunes and remains as a valid option to faithful Catholics throughout the world.