An average 1962-rite Mass attender would see little different at an 1863 Mass if he attended one without a Missal. He might note rather more collects, secrets and postcommunions; he might wonder at the Last Gospel often not being that of the beginning of St John's Gospel; he wouldn't actually hear St Joseph not being mentioned in the Canon of the Mass. If he attended at Holy Week, he would see a radically different celebration to that offered by his 1962-rite parish, but between Paschaltides, there would be few clues to suggest that the difference was, in fact, massive. Two things might surprise him: Holy Communion would not be routinely received by the faithful during Mass, and the beginning of Mass would not be earlier than an hour before first light (by the sun, not by an arbitrary rule) or later than 1.00 pm. (If Mass is a re-presentation of the Sacrifice of Jesus, then the modern insistence on receiving hosts consecrated at the Mass one attends begins to look a bit odd.)
In fact, the thing that makes the Mass so different is the calendar, and the ranking of feasts in the calendar; the fact that Sundays do not necessarily take precedence over other feasts; and the fact that each diocese has its own version of the Roman Calendar.
Though what follows may seem complicated, it isn't: any - in fact every - literate Catholic was expected to be able to work out the correct readings for any day if he had a Missal. There was no TV in those days, so there was plenty of time to work out the week's celebrations, and, anyway, ecclesiastical almanacs were cheap to buy.
Every day either had a feast or hadn't: a feast would be a Double, a Semi-double, or a simple; if there was no feast the day would be a feria. There were five sorts of Doubles, in order: Doubles of the first class, Doubles of the second class, greater Doubles, Doubles and semi-Doubles. Simples were, simply, simples.
Sundays followed a different system: they might be privileged of the first class, or of the second class, which governed which Mass might be said on them. In any case, however, the prayers (the collective term for the proper collect, secret and postcommunion) for the Sunday would be said, as would its Gospel. If the Sunday's precedence was less than that of a feast which fell on Sunday, then the Gospel of the Sunday would be said as the Last Gospel.
The rules of precedence meant that some feasts would have to be transferred from their normal day to the next available, as All Souls this year has been transferred to 3 November because the Sunday in the Octave of All Saints has a higher precedence than All Souls. Over the year, this can mean significant movement of feasts, some being celebrated (at least in some dioceses) up to a couple of months after their due date.
In general, though, unless the feast is a very important one a number of prayers will be said to draw in all of the relevant commemorations due on the day. And, if the feast isn't too important, the priest can add other prayers, from those listed in the Missal for special intentions. There must be no more than five; well, there must be no more than seven. If there are more than three, there must be either five or seven, unless there are four. Yes, it's complicated, but remember those long winter evenings.
I will do all this for you for this year (except add the priest's own extras), but what looks like a mess is in fact a natural growth over the preceding centuries. The modern idea of "St Sunday" - Sunday taking precedence over almost any calendar feast - is totally alien to the way the liturgy was celebrated for at least ten centuries before the twentieth. The liturgical year has a rhythm which marks Sunday as the weekly day of precept, not as a sort of Sabbatarian dictator.
What I hope you will see is variety, a three dimensional calendar which marks how things are rather than how things should be according to some arbitrary rule.
Next article: parish life.