In a nearby parish they celebrate a Mass on Saturday morning as the vigil Mass for Sunday. Is this permitted? Also, if I attend a wedding Mass on Saturday afternoon, does this fulfil my obligation to attend Mass on Sunday?
Before I answer your questions, it will be helpful to look at the history of vigil Masses. Vigils go back to the Old Testament, where the Jewish sabbath began at sunset the previous day. We see this, for example, when Christ and the two thieves were taken down from the cross on Good Friday before the beginning of the sabbath.
St John relates: “Since it was the day of Preparation, in order to prevent the bodies from remaining on the cross on the sabbath (for that sabbath was a high day), the Jews asked Pilate that their legs might be broken, and that they might be taken away” (Jn 19:31). To this day, Jews begin their sabbath celebration at sunset on Friday evening.
Also, the early Christians and other peoples at that time divided the day into four night watches, or hours, and four daytime ones, each of three hours.
The day began with the first watch at sunset, at approximately 6pm. From the earliest times too, Christians celebrated Easter, beginning with the Easter Vigil on Saturday evening.
And since the early centuries, the liturgical day for Sundays and important feasts in the Divine Office begins with First Vespers in the evening on the preceding day.
In modern times, on 6 January 1953, Pope Pius XII issued the Apostolic Constitution Christus Dominus, which granted bishops the faculty of permitting Masses to be said in the evening on certain occasions, for example before a holy day of obligation. It stipulated that these Masses were not to be said before 4pm (cf. Rule VI).
Then, after the Second Vatican Council (1962-65), vigil Masses were allowed on all Sundays. The Instruction on the Worship of the Eucharistic Mystery Eucharisticum Mysterium, issued by the Sacred Congregation of Rites on 25 May 1967, stated: “The purpose of this concession is in fact to enable the Christians of today to celebrate more easily the day of the resurrection of the Lord. All concessions and contrary customs notwithstanding, when celebrated on Saturday this may be celebrated only in the evening, at times determined by the local ordinary” (n. II, C).
With this background, it is clear that vigil Masses are to be celebrated only in the evening. The local bishop can determine the times for these Masses, provided they are in the evening.
The times might vary between summer and winter, when sunset is at very different times, especially in countries in the far North and far South. Following Pope Pius XII’s declaration that they were not be celebrated before 4pm, many commenters and bishops have accepted this as the very earliest time.
In the diocese of Rome and many other places, the earliest vigil Masses are at 5pm. It would not make sense to have a vigil Mass any earlier than 4pm, since no one would consider such a Mass to be celebrated in the evening.
As for wedding Masses on Saturday, the Code of Canon Law says with respect to the obligation of attending Mass on Sundays and holy days of obligation: “The obligation of participating in the Mass is satisfied when one assists at Mass wherever it is celebrated in a Catholic rite, either on a holy day itself or on the evening of the previous day” (Can. 1248, §1).
This has been interpreted to mean that as long as the Mass is in a Catholic rite, regardless of whether the liturgy is of Sunday or of some other rite like a wedding or funeral, one fulfils the Mass obligation. Usually when a wedding is celebrated on a Sunday or late on Saturday, at least some elements of the Sunday Mass are to be included, for example the profession of faith and possibly one or more of the readings.
Therefore, a wedding celebrated at 4pm or later would obviously count for Sunday, but one celebrated any earlier would be doubtful, as it would not have the sense of being an evening Mass.