I'm clearly saying the opposite, that the "Vigil" Mass of the day before Christmas is not Christmas Mass.

You are very confused.  Mass on the day before Christmas isn't actually the Vigil in the same sense as the Easter Vigil, but was merely the Mass for the day before Christmas.  One of the few other "Vigils" that was retained through pre-1955 to compare it to is that of Pentecost.  Rest of them slowly fell into disuse and were no longer true Vigils.

For the last time, the Vigils themselves were NOT the actual Masses of the feast, but, as the name implies, a set of services, consisting of sung Psalms, readings, etc. that went through the night in anticipation of and leading up to the actual Mass of the Feast itself.  That's what the term "vigil" actually means in Latin, a night-watch.  So they stayed up all night in anticipation of the Feast itself.  If today there's a "Mass" on the "Vigil" of Christmas (where the term had just loosely been transferred to mean "the Day Before"), that's just because the Vigil itself felt into disuse and was no longer celebrated as a true Vigil.

I understand what a Vigil meant to the early Church but those are essentially no longer kept. The Church herself refers to the penitential Masses the day prior to major feasts as Vigils which is where the confusion arises. While I am a Latin rite Catholic at heart I have become very familiar with the Byzantine rite as most of us are in exile from the true Mass. In the Byzantine rite there is a Divine Liturgy on the morning of Holy Saturday. The Liturgy is very solemn but also hopeful, it can have more than 15 old testament prophecies similar to the 12 in the pre 55. During this the hymns point us to reflect on the fact that Our Lord is in the tomb as well as all of salvation history. Between 11pm and midnight Paschal Matins start with the Paschal Divine Liturgy always starting after midnight on Easter proper.


To me it seems that the pre 55 Easter Vigil was similar to the Divine Liturgy of Holy Saturday morning and the proper Mass of Easter to the midnight Paschal Liturgy. However, what I am gathering from your comments is that Holy Saturday in the West was aliturgical.