Little is known of St. Maximus, besides his writings and the fact that he was Bishop of Turin. It is thought he was a native of Rhaetia, in modern northern Italy, possibly born in the town of Vercelli. Some think he is the same Maximus who attended a few local synods and councils—the Synod of Milan in 451 and the Council of Rome in 465 (thus giving him a much longer life), but there is no certainty. What has truly cemented his legacy is a large collection of homilies and sermons, along with a few treatises. An interesting aspect of this homily is the fact that it explicitly discusses the connection between the dating of Christmas and the Roman feast of the "new sun" or "Sol Invictus" (Unconquered Sun). The paragraph divisions below are my own.
Well, in a way, does the common man call this holy day of the Lord’s nativity “the new sun,” [1] and He confirms such things by His authority, so that the Jews as well as the Gentiles consent in this name. Which is to be freely expanded by us, since, the Savior dawning, not only the salvation of the human race, but also the clarity of the sun itself is renewed. [2] As the Apostle says: So that all would be renewed through Him, either those which are in heaven, or those on earth (Eph 1:10). For if the sun is obscured when Christ suffers, it is necessary that it shine with a most splendid light when He is born. And if darkness pours out on the Jews working death, why does it not show clarity at Mary’s giving birth to life? Or do we not believe that, Christ being born, the sun came to a more lucid compliance, when the clearer star preceded, with the magi, as a sign? And if the star performed the office of day in a strange time, why do we not believe, that the sun also plucked a little of the night hours by a more mature coming? From this, therefore, I think it a fact, that night would decrease, when the sun, hastened by compliance to the Lord’s nativity, brings light before the world, instead of the night consummating its course in its time. No, I do not say that night would be more powerful, nor have any obscurity, in which the shepherds keep vigil, the angels exult, the stars serve. We ought not to wonder that, in the nativity of Christ, all things are made new, when it was new itself, that a virgin gave birth. But if the nativity exists beyond custom, and, beyond custom, compliances are removed, therefore, the Lord dawning, shepherds keep vigil, angels exult, the sun obeys, the stars serve. And since the angels or shepherds accompany with joy by their voice or sermons; yet the elements protest their own joys by office, since they cannot by voice. Therefore, the sun, beyond custom, shone at morning on this festivity; nothing miraculous: for if, at the prayer of Jesus, son of Nun, [3] it stood fixed in the day (cf. Jos 10), why, in Jesus Christ’s nativity, does it not, hastening, advance in the night? Therefore, the common man calls this day “the new sun,” and, when he says “new,” he thereby also demonstrates it to be old.
But I would call the sun of this world “old,” which suffers defection, which is excluded by walls, which is obscured by clouds. I would call the sun “old,” which is subjected to vanity, which fears corruption, which is terrified by judgment. For it is written: The sun will turn into darkness, and the moon into blood (Joel 2:31; Acts 2:20). I say, I would call “old” that which is amidst men’s wicked deeds, does not flee adultery, does not decline from homicide, and, when it does not want to be in the midst of the whole human race, when any crime is admitted, this sun stands amid all the deeds. Therefore, since it is clear this is old, let us find a new which is nothing but Christ the Lord, of Whom it is written: The sun of justice will dawn upon you (Mal 4:2); of Whom also the prophet speaks, in the person of sinners: The sun did not dawn on us, and the light of justice did not lighten us (Wis 5:6). For this sun, when the whole world was oppressed by the devil’s darkness, and a fog full of crimes possessed the age, deigned, in the last time, that is, the now incumbent night, to pour forth the dawn of His nativity. Since first, before the light, that is, before the Son of justice illuminated, or at morning, one of the prophets sent an oracle: I will send my prophets before the light (Jer 25:4); [4] afterwards, truly, He with His rays, that is, with the radiance of the apostles, shone forth, and dispersed the world’s fog by the truth’s light, so that no one would stumble in the devil’s darkness. He is, therefore, the new sun Who penetrates the closed, unlocks the depths, tears open hearts. He is the new sun Who, by His spirit, vivifies the dead, repairs the corrupt, arises those already dead; or Who, by His heat, purges the sordid, dries up the moist, boils away faults. He, I say, is He Who, in all our acts, looks at all our deeds, and He not so much condemns crimes as emends them. He, plainly, is the just and wise sun which, not without discretion, like this world’s sun, circles the good and evil, but that shines with the holy judgment of truth, slays sinners. But that sun is amid both, since it is the minister of corruption, but this is the Lord of eternity: since that one is around the earth, this one the Creator: yet before this sun dawns in the world, while yet before the light, according to the necessary use of men, the lamp ought to precede. But Christ the sun also has His lamp, which precedes His advent: as the Prophet says: I prepared a lamp for my Christ (Ps 131:17). But who this lamp is, the Lord shows us, saying of John the Baptist: He was a burning lamp (Jn 5:35). But the same John, as the paltry light of a lamp preceding, says: Behold, He comes after me, of Whom I am not worthy to loose the thong of His sandals: He will baptize you in the Holy Spirit and fire (Jn 1:27; Mt 3:11). At the same time, also understanding his light to be obfuscated by the sun’s rays, he preaches before Him: It behooves Him to grow, but me to diminish (Jn 3:30). For as the clarity of the lamp is destroyed by the sun’s advent, so also John’s baptism of penitence is emptied by the coming of Christ’s grace.
Therefore, we see here, from which font our new sun is born. As, it is true, He dawns from God, the author. Therefore, He is Son of divinity; of divinity, I say, incorrupt, integral, complete. I plainly understand a mystery; for, therefore, the nativity is fruitful through the immaculate Mary, since, before, He was constituted complete through divinity: Whose first nativity stood glorious, His second will not be reproachful. That is, as, in some way, the virgin divinity gave Him forth, so also the virgin Mary generated Him. It is even written that He has a father among men; as we read in the Gospel, the Pharisees saying: Is this not the son of Joseph the carpenter, and His mother Mary? (Mt 13:55) In this, also, look to the mystery. Christ’s father is said to be a carpenter. And, clearly, God the Father is a carpenter, Who built the whole world’s works; He is clearly a craftsman, but He Who ordered Noah to build an ark during the flood. [5] A carpenter, I say, is He Who ordained Moses’ tabernacle, instituted the ark of the testament, erected the temple of Solomon; I would call Him a carpenter, Who smooths rigid minds, pares down proud thoughts, raises humble deeds. Indeed, this carpenter uses curved iron tools around trees, as we read in the Gospel, John saying: Now the axe is placed at the root of the trees. Every tree not bearing good fruit will be cut down, and thrown into the fire (Mt 3:10; Lk 3:9); as tool of the heavenly carpenter builds trees for the future, but the fire of flames consumes the unfruitful, plucked out by the root.
Footnotes: [1] It is commonly known that the date of December 25th to celebrate Christmas was, at least to some degree, chosen because of a Roman celebration of the “Invincible Sun” or the winter solstice, on that day. Previously, there was a combined feast of the Lord’s Birth and Baptism on January 6, before the Nativity was split off to its own date (although the Armenians still celebrate the single feast).
[2] SInterestingly, the Latin word for “to renew,” like its Greek counterpart, can also mean “to institute” or “to introduce”; thus this could be read as saying that humanity’s salvation was introduced at Christ’s birth.
[3] In Greek and (presumably) Hebrew, both Joshua and Jesus share the same name; many Latin writers also took up the habit of calling Joshua “Jesus.” He is characterized by calling him “of Nun” (or “Nave,” from the Greek).
[4] This appears to be an old, pre-Vulgate Latin version of this verse. It is also quoted, in a similar form, by Lactantius (c. 250 – c. 325), in his Divine Institutions IV.11, and by St. Cyprian (c. 200 – 9/14/258) in his Against the Jews I.1.2.
[5] In Latin, the word here used for “to build” is connected to the word “carpenter”: fabrico vs. faber.
Source: Patrologiae Cursus Completus, Series Latina, ed. J.-P. Migne, Tomus LVII (Paris: J.-P. Migne, 1862), 537C-540C. [PL 57:537C-540C]