I will be frank with you: I do not know when Christmas was invented. I accept provisionally the theory that, the Lord's Passion having been dated to March 25, His Conception was assumed to be on that same date, so that December 25 appears as His Day of Birth. I certainly don't believe that Christmas is a Christianisation of the pagan festival of the Unconquered Sun. When, in a day or two's time, some pompous journalist or other informs us of that, remember that historical consensus is now that Sol Invictus is a late paganisation of Christmas, rather than the other way round.
This week we observe in the Roman Rite the Advent Ember Days. Originally, there were only three Ember periods ... the Lent Ember is a later confection. So we have the Embers now fixed on Whit Week, which many of us think perpetuates the Pagan Roman Wheat Harvest; the September Ember week, occupying the same slot as the Roman Vintage celebrations; and this week's Ember, which comes at the same time as the feriae sementinae (or sementivae): "Sowing Time". (For the Hebrew background, vide Zech. 8:19.)
And these splendid Traditional seasons are, in their origins, Fasts. Just so, the pagan festivals were periods when the Romans begged the gods to stay away from the crops. Forget the rich pantheon of anthropomorphic Greek divinities: the Romans, until they became Hellenised, trafficked with gods such as Mildew (Robigo); they sacrificed to him (or her?) to stay away from their fields and crops. It has been wittily and justly observed that, if the Romans had had bicycles, they would have sacrificed to Punctura to get her (or him?) to stay away from their tyres.
Perhaps this is at least one contributory reason why, historically, the Embers were fasts rather than festive Victorian Anglican occasions for parish merriment and great heavy plonking metrical hymns (... the Good seed in the land ...). Those who say the Breviary Office will recall that, yesterday in the second nocturn, S Leo reminded his hearers decimi mensis celebrandum esse ieiunium, quo pro consummata perceptione omnium fructuum, dignissime largitori eorum Deo continentiae libamen offertur.)
There is evidence that this week's Ember, the Ember of the tenth month, was originally the senior Ember, only occasion when Ordinations happened in Rome.
Did I say "Tenth"?
To be concluded.