Votive Mass

In the liturgy of the Roman Catholic Church, a votive Mass (Latin "missa votiva") is a Mass offered for a "votum", a special intention.
The Mass does not correspond to the Divine Office for the day on which it is celebrated. Every day in the year has appointed to it a series of canonical hours and (except Good Friday) a Mass corresponding, containing, for instance, the same collect and the same gospel. Normally the Mass corresponds to the Office, but on occasion, may not.
History.
The principle of the votive Mass is older than its name. Almost at the very origin of the Western liturgies (with their principle of change according to the Calendar) Mass was occasionally offered, apparently with special prayers and lessons, for some particular intention, irrespective of the normal Office of the day. Among the miracles quoted by Augustine of Hippo in "De civ. Dei", XXII, 8, is the story of one Hesperius cured of an evil spirit by a private Mass said in his house with special prayers for him—a votive Mass for his cure.
The first sacramentaries contain many examples of what we should call votive Masses. So the Leonine book has Masses "in natale episcoporum" (ed. Feltoe, pp. 123–26), "de siccitate temporis" (ed. Feltoe, 142), "contra impetitores" (ed. Feltoe, 27), and so on throughout. Indeed, the Masses for ordination and for the dead, which occur in this book and throughout the Roman Rite and Gallican Rite, are examples of votive Masses for all kinds of occasions, for ordinations (ed. Wilson, pp. 22–30, etc.), for those about to be baptized (ed. Wilson 34), anniversaries of ordinations (153-54), nuns (156), for the sick (282), for marriages (265), kings (276), travellers (283), the dead (301 sq.), and a large collection of Masses of general character to be said on any Sunday (224-44). In this book the name first occurs, "Missa votiva in sanctorum commemoratione" (p. 367; Rheinau and S. Gallen MSS.). The Gregorian Sacramentary, too, has a large collection of such Masses and the name "Missa votiva" (e.g., "Patrologia Latina", LXXVIII, 256).
Throughout the Middle Ages the votive Mass was a regular institution. The principle came to be that, whereas one official (capitular) high Mass was said corresponding to the Office, a priest who said a private Mass for a special intention said a votive Mass corresponding to his intention. The great number of forms provided in medieval Missals furnished one for any possible intention. Indeed, it seems that at one time a priest normally said a votive Mass whenever he celebrated. John Beleth in the thirteenth century describes a series of votive Masses once said ("fuit quoddam tempus") each day in the week: on Sunday, of the Holy Trinity; Monday, for charity; Tuesday, for wisdom; Wednesday, of the Holy Ghost; Thursday, of the Angels; Friday, of the Cross; Saturday, of the Blessed Virgin (Explic. div. offic., 51). This completely ignores the ecclesiastical year.
But there was a general sentiment that, at least on the chief feasts, even private Masses should conform to the Office of the day. The Feast of the Holy Trinity began as a votive Mass to be said on any Sunday after Pentecost, when there was no feast.
Bible and doctrine.
The Solemnity of Pentecost celebrates Jesus' gift of the Holy Spirit God to the Apostolic Church, followed by its power of remitting sins and exorcizing demons, like Jesus did in His miracles. The Lord hastened to St Peter the same authority, appointing him as the first pope ("rock") of the Church. The same charisms of the Holy Spirit God were used and revealed by Jesus Christ God in the Harrowing of Hell, and also are attributed to the St Michael the Archangel, whose exorcistic prayer (called "Exorcism against Satan and the apostatic angels") is able to win Satan and all the angels pertaning to his mystical body. The Bible also mentions Raphael the archangel and the Book of Tobit against the strong demon Asmodeus.
Suffrage Mass.
The Suffrage Mass is a particular type of Votive Mass in which one or more Roman Catholic baptized believers ask to the celebrating priest to offer a Mass to God in favour of the salvation of one or more souls temporary living in the Purgatory.
While the Holy Mass is always offered to God, it can also be dedicated to one or more Roman Catholic saints in order to ask their intercessory prayer to God.
The Council of Trent stated the belief in the intercession of saints as a canon any Roman Catholic is obliged to believe.
For the Roman Catholic doctrine, any saint may pray God to intercede his divine grace in favour of any human living being, but within a hierarchical order of intercessory power: first Jesus Christ God by way of Mass (worship), secondly the Blessed Virgin Mary (hyperdulia), thirdly Saint Joseph (protodulia), and lastly the hierarchy of angels.
The pious practice of the Suffrage Mass is also founded on the belief in the existence of the Purgatory. For the Roman Catholic faith, at the time of the death there is a separation of the soul form the earthly body. The soul undergoes to the particular judgment of God who is Omniscient and therefore can't fail in his judgement. The judgement is based on the personal sins and merits of salvation acquired during the earthly life. The sol can't do anything to improve its afterlife condition after the death. There are three possible judgements of God corresponding to as many possible destinations of the soul: Paradise, Purgatory and Hell.
Solely the soul who died in sanctity, to say without any stain of personal sin and also without the original sin, can be admitted in Paradise. Otherwise, if they have committed some mortal sins which weren't absolved by a priest before their death, the destination is the Purgatory.
The soul is believed to stay in Purgatory for a finite time in order to repair its sins and have them forgiven by God. Thi is a concern for all the sins that weren't confessed and absolved before the death. The expiation is necessary before the expiating souls can be admitted in Paradise. 
The number of months or of years of its duration is believed to be proportional to the gravity of the guilts committed during the earthly life.
The Suffrage Mass is believed to have the power to shorten the expiating period if God decides to grant the grace of a lower penalty for the souls to which the Mass is directed. The prayer of saints to God can contribute to reach the same purpose.
When the expiation time had finished, St Michael the Archangel is believed to go in the Purgatory to liberate the expiating souls and bring them in Paradise. Paradise is dedicated to the vision of the truth and contemplation of the Face of God, which is the highest and last purpose of the human life. There, hierarchy of angels and souls pray and worship God, and live forever in communion while waiting the expiating souls of the Purgatory be definitely saved and any souls can get its resurrected flesh at the end of times.
Rulings.
This idea of allowing votive Masses to be said only when no special feast occurs finally produced the rules contained in later missals (1570). According to these, there is a distinction between votive Masses strictly so called and votive Masses in a wider sense. The first are those commanded to be said on certain days; the second kind, those a priest may say or not, at his discretion.
Strict votive Masses are, first, those ordered by the rubrics of the Missal, namely a Mass of the Blessed Virgin on every Saturday in the year not occupied by a double, semi-double, octave, vigil, feria of Lent, or ember-day, or the transferred Sunday Office (Rubr. Gen., IV, 1). This is the "Missa de S. Maria" in five forms for various seasons, among the votive Masses at the end of the Missal. To this we must add votive Masses ordered by the pope or the ordinary for certain grave occasions (pro re gravi). Such are for the election of a pope or bishop, in time of war, plague, persecution, and so on.
Such votive Masses may be ordered by the ordinary on all days except doubles of the first or second class, Ash Wednesday, and the ferias of Holy Week, the eves of Christmas and Pentecost; except also days on which the office is said for the same intention or event as would be prescribed by the votive Mass. In this case the Mass should conform to the office as usual. A third kind of strictly votive Mass is that said during the devotion of the so-called "Forty Hours". On this occasion the Mass on the first and third days is of the Blessed Sacrament; on the second day it is for peace. But on doubles of the first and second class, Sundays of the first and second class, on Ash Wednesday, in Holy Week, during the octaves of Epiphany, Easter, Pentecost, on the eves of Christmas and Pentecost, the Mass of the day must be said, with the collect of the Blessed Sacrament added to that of the day under one conclusion.
The other kind of votive Mass ("late sumpta") may be said by any priest on a semidouble, simple or feria, at his discretion, except on Sunday, Ash Wednesday, the eves of Christmas, Epiphany, Pentecost, during the octaves of Epiphany, Easter, Pentecost, Corpus Christi, Holy Week, and on All Souls' Day. Nor may a votive Mass be said on a day whose Office is already that of the same occasion; but in this case the corresponding Mass of the day must be said, according to the usual rubrics. A votive Mass may be taken from any of those at the end of the missal, or of the common of Saints, or of their propers, if the text does not imply that it is their feast. A Sunday or ferial Mass may not be used as a votive Mass. Nor may it be said of a Beatus, unless this is allowed by special indult.
The Gloria is to be said in votive Masses "pro re gravi" unless the colour be violet; also in votive Masses of the Blessed Virgin on Saturday, of angels, whenever said, in those of saints, when said on a day on which they are named in the Martyrology or during their octaves. The Creed is said in solemn votive Masses pro re gravi. The first and third Masses of the Forty Hours have the Gloria and the Creed, not the Mass for Peace (but if said on a Sunday it has the Creed). Solemn votive Masses have only one collect; others are treated as semidoubles, with commemorations of the day, etc., according to the usual rule. The colour used for a votive Mass corresponds to the event celebrated, except that red is used for Holy Innocents. It is red for the election of a pope, white for the anniversary of a bishop's election or consecration, violet in the general case of asking for some special grace and for the Passion.
The particular case of votive Masses for each day of the week, corresponding to votive Offices ordered by Pope Leo XIII, was abolished by the Decree "Divino afflatu" of 1 November 1911. Requiems and Masses for marriages are really particular cases of a votive Mass.