The interpretation timeline
Psalm 73:14 Douay-Rheims

Thou hast broken the heads of the dragon: thou hast given him to be meat for the people of the Ethiopians.

A.D. 386 – 1849 5 witnesses

Patristic

before A.D. 750
386
A.D.
Cyril of Jerusalem Patristic
A.D. 313–386
“Jesus sanctified Baptism by being Himself baptized. If the Son of God was baptized, what godly man is he that despiseth Baptism? But He was baptized not that He might receive remission of sins, for He was sinless; but being sinless, He was baptized, that He might give to them that are baptized a divine and excellent grace. For since the children are partakers of flesh and blood, He also Himself likewise partook of the same, that having been made partakers of His presence in the flesh we might be made partakers also of His Divine grace: thus Jesus was baptized, that thereby we again by our participation might receive both salvation and honour. According to Job, there was in the waters the dragon that draweth up Jordan into his mouth. Since, therefore, it was necessary to break the heads of the dragon in pieces, He went down and bound the strong one in the waters, that we might receive power to tread upon serpents and scorpions. The beast was great and terrible. No fishing-vessel was able to carry one scale of his tail: destruction ran before him, ravaging all that met him. The Life encountered him, that the mouth of Death might henceforth be stopped, and all we that are saved might say, O death, where is thy sting? O grave, where is thy victory? The sting of death is drawn by Baptism.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“What more after the heads of dragons? For those dragons have their chief, and he is himself the first great dragon. And concerning him what hath He done that hath wrought Salvation in the midst of the earth? Hear: "Thou hast broken the head of the dragon" (ver. 14). Of what dragon? We understand by dragons all the demons that war under the devil: what single dragon then, whose head was broken, but the devil himself ought we to understand? What with him hath He done? "Thou hast broken the head of the dragon." That is, the beginning of sin. That head is the part which received the curse, to wit that the seed of Eve should mark the head of the serpent. For the Church was admonished to shun the beginning of sin. Which is that beginning of sin, like the head of a serpent? The beginning of all sin is pride. There hath been broken therefore the head of the dragon, hath been broken pride diabolical. And what with him hath He done, that hath wrought Salvation in the midst of the earth? "Thou hast given him for a morsel to the Ethiopian peoples." What is this? How do I understand the Ethiopian peoples? How but by these all nations? And properly by black men: for Ethiopians are black. They are themselves called to the faith who were black; the very same indeed, so that there is said to them, "for ye were sometime darkness, but now light in the Lord." ...Thence was also that calf which the people worshipped, unbelieving, apostate, seeking the gods of the Egyptians, forsaking Him who had delivered them from the slavery of the Egyptians: whence there was enacted that great Sacrament. For when Moses was thus wroth with them worshipping and adoring the idol, and, inflamed with zeal for God, was punishing temporally, in order that he might terrify them to shun death everlasting; yet the head itself of the calf he cast into the fire, and ground to powder, destroyed, strawed on the water, and gave to the people to drink: so there was enacted a great Sacrament. O anger prophetic, and mind not perturbed but enlightened! He did what? Cast it into the fire, in order that first the form itself may be obliterated; piece by piece grind it down, in order that little by little it may be consumed: cast it into the water, give to the people to drink! What is this but that the worshippers of the devil were become the body of the same? In the same manner as men confessing Christ become the Body of Christ; so that to them is said, "but ye are the Body of Christ and the members." The body of the devil was to be consumed, and that too by Israelites was to be consumed. For out of that people were the Apostles, out of that people the first Church. ...Thus the devil is being consumed with the loss of his members. This was figured also in the serpent of Moses. For the magicians did likewise, and casting down their rods they exhibited serpents: but the serpent of Moses swallowed up the rods of all those magicians. Let there be perceived therefore even now the body of the devil: this is what is coming to pass, he is being devoured by the Gentiles who have believed, he hath become meat for the Ethiopian peoples. This again, may be perceived in, "Thou hast given him for meat to the Ethiopian peoples," how that now all men bite him. What is, bite him? By reproving, blaming, accusing. Just as hath been said, by way of prohibition indeed, but yet the idea expressed: "but if ye bite and eat up one another, take heed that ye be not consumed of one another." What is, bite and eat up one another? Ye go to law with one another, ye detract from one another, ye heap revilings upon one another. Observe therefore now how that with these bitings the devil is being consumed. What man, when angry with his servant, even a heathen, would not say to him, Satan? Behold the devil given for meat. This saith Christian, this saith Jew, this saith heathen: him he worshippeth, and with him he curseth! ...”
Source

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“the heads of Leviathan Pharaoh is called [by] this [name], as it is said (Isa. 27:1): “the Lord will visit with His hard...sword on leviathan, etc.” You give it as food to the people in companies You gave his money to the people of Israel to consume. in companies Heb. לציים. To the companies and hosts that You took out. ציים are companies, as (Num. 24:24): “And companies from the Kittites,” which is translated as וסיען, and companies.”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Thou didst cleave the fountain and the flood,.... That is, the rocks at Horeb and at Kadesh, from whence water flowed as out of a fountain, and became a flood, whereby the people of Israel were supplied with water in the wilderness, and also their beasts; and from this instance it may be concluded that God will not leave his people, nor suffer them to want, but will supply all their need while they are in the wilderness, and will open fountains and rivers for them, Isa 41:17 he himself is a fountain of living water; Christ is the fountain of gardens, and the Spirit and his grace a well of living water springing up unto everlasting life: thou driedst up mighty rivers; the river of Jordan, called "mighty", as Kimchi says, because by its strength it overflowed all its banks and "rivers", and because other rivers flowed into it; this was dried up, or way was made through it, as on dry land, for the people of Israel to pass into Canaan, Jos 3:14, the Targum is, "thou hast dried up the fords and brooks of Hermon, and the fords of Jabbok and Jordan;'' see Num 21:14, and the Lord, that did this, is able to dry up, and will dry up, the river Euphrates, as is foretold, Rev 16:12, that is, destroy the Turkish empire, and make way for the spread of the Gospel in the eastern parts of the world; to which reference is had in Isa 11:15.”
Source
1849
A.D.
1774–1849
“Ethiopians. Or to enrich the Arabs. (Menochius) — Hebrew Tsiim, is understood of sailors, and “fishermen,” &c., Psalm lxxi. 9. Some nations of Ethiopia are said to be cannibals; but they were too distant from the Red Sea. The Ichnyophagi or Troglodytes on the western banks, might despoil the dead, (Calmet) and procure food, (Haydock) unless this be a description of a great fish, slain by the power of the Almighty, and really eaten. (Calmet) — Many explain these people, to mean wild beasts, which devoured the carcasses. (Eusebius; Muis)”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.