Let's start with the circumcision entry in the International Bible Encyclopedia:
A peculiar martial custom is mentioned in 1 Sam 18:25,27 (compare 2 Sam 3:14), where Saul is represented as asking "a hundred foreskins of the Philistines" as a dowry from David for the hand of Michal. This does not seem to have been an exceptional booty in war, especially if it meant that no very careful operation was expected to be performed, but the act became practically equivalent to extermination. We find in Egyptian history at the time of Ramses III, that an invasion into Egypt had been made by several Libyan tribes (see Diimichen, Histor. Inschr., I, plates I-VI, and II, plates 47 ff). The Egyptian army sent against the invaders defeated them and returned with a large number of karnatha which is a transcription into hieroglyphics of the Semitic word, qarenoth, the word being used euphemistically as is proven by the accompanying determinative sign of a phallus. See Chabas, Etudes sur l'antiquite historique d'apres lee sources egyptienne,, etc., 234; Bondi, Hebr.-Phoen. Lehnworte im Egyptischen, Leipzig, 1886, 72-74.
And here is another reference to the same archaeological evidence with a slightly different take:
Normal Egyptian practice was to cut off the hands of enemies slain in war so that accurate counts could be made after a battle, but in a text about the battles of Merneptah against the Libu and Sea Peoples it is said that in some cases they cut off the phalli. These phalli are said to have to have kernata, a foreign word (used only in two Egyptian texts) which is often taken to mean sheath (see eg Naville l900: 68) but which, it has also been argued (partly on linguistic grounds) could equally well mean prepuce (see eg Holscher l955: 43-5; Bates 1914: 122 - 4). Accepting the latter argument, Egyptian practice would have been to cut off the hands of those enemies who were circumcised and to cut off the phalli of the uncircumcised. If this is the correct interpretation, it would mean that we it would mean that we still do not know the Egyptian word for penis sheath, although it has been suggested that there was such a word used in connexion with priests whose duties included the clothing of god and king (Grdseloff l943: 357-66). Actual depictions of Merneptah's battles, as well as the later ones of Rameses III, show actual heaps of hands and phalli with testicles, and the bodies shown appear to have either hands or unsheathed penes. By the time of Rameses III the word kernata clearly referred to the phallus and not merely the foreskin if the evidence from the representations can be accepted. This is perhaps the major reason against accepting the equation between foreskin and kernata, but it should be noted that similar extensions of meaning occur in Hebrew for the Semitic word which kernata represents. [Victor Buchli, Material culture: critical concepts in the social sciences, Volume 1, Part 2 p. 257]
The Arabic word ghurlatun is connected by many studies with the ancient Egyptian Karnatha (Garnatha).
In recent times scholarship seems to have come around to thinking that qrnt means 'foreskin.' Here is another explanation of the Merneptah reference. It is important to note that the word qrnt appeared in late Egyptian.
It is worth noting that Irenaeus connects 'Cerinthus' with the Gospel of Matthew and so-called 'Jewish Christianity.'(AH i.26.2) As Stephen Carlson has aptly shown Lines 42-46 of the Muratorian canon invite comparison to certain passages from Dionysius bar Salibi and Epiphanius of Salamis. These lines run as follows:
Primum omnium Corinthiis schisma haeresis in terdicens, deinceps Galatis circumcisionem, Romanis autem ordine scripturarum, sed et principium earum esse Xr{istu}m intimans prolixius scripsit.
First of all to the Corinthians against the schism of heresy, then to the Galatians against circumcision; to the Romans, however, he wrote rather at length, but also intimating by an order of scriptures that Christ was their beginning.
Dionysius bar Salibi, introduction to Commentary on the Apocalypse (modern Latin provided by I. Sedlacek):
Ille quidem Cerinthus docebat circumcisionem, et iratus est in Paulum quod non circumciderat Titum, et vocat apostolum eiusque discipulos in quadam e suis epistulis apostolos falsos et operarios fallaces. docebat etiam mundum ab angelis creatum esse; et non e virgine dominum nostrum natum esse, et cibum et potum materiales, et multas blasphemias.
This Cerinthus indeed used to teach circumcision, and was angry against Paul because he did not circumcise Titus, and he calls the apostle and his disciples in some of his letters false apostles and workers-for-hire. He also used to teach that the world was created by angels, and that our Lord was not born from a virgin, and the importance of food and drink, and many blasphemies.
From Epiphanius, Panarion 28.1:
Τα ισα γαρ τω προειρημενω εις τον Χριστον συκοφαντησας εξηγειται και ουτος εκ Μαριας και εκ σπερματος Ιωσηφ τον Χριστον γεγεννησθαι και τον κοσμον ομοιως υπο αγγελων γεγενησθαι.
For [Cerinthus] too slanders the same things as the aforementioned [Carpocrates] against Christ and provides the exegesis that Christ was born from Mary and from the seed of Joseph and that the the world likewise was made by angels.
From Epiphanius, Panarion 28.4:
Αλλα ταυτα μεν τοτε επραγματευθη κινηθεντα υπο του προειρημενου ψευδαποστολου Κηρινθου, ως και αλλοτε στασιν αυτος τε και οι μετ᾿ αυτου ειργασαντο εν αυτη τη Ιερουσαλημ, οπηνικα Παυλος ανηλθε μετα Τιτου και ως ουτος εφη οτι, Ανδρας ακροβυστους εισηνεγκε μεθ᾿ εαυτου, ηδη περι Τιτου λεγων· Και κεκοινωκε τον αγιον τοπον. ....
But these things were instigated, set into motion by the aforementioned false apostle Cerinthus, as also at another time he himself and those with him worked out a tumult in Jerusalem itself, when Paul came up with Titus and [Cerinthus] said: He has brought uncircumcised men in with him, now saying concerning Titus: And he has made the holy place common. ....
Και ουτοι εισιν οι παρα τω αποστολω Παυλω ειρημενοι· Ψευδαποστολοι, εργαται δολιοι, μετασχηματιζομενοι εις αποστολους Χριστου.
And these are those about whom it has been said by the apostle Paul: False apostles, deceitful workers, transforming themselves into apostles of Christ.
I am beginning to suspect that Petrement's argument about a relationship between Cerinthus and Corinthos is actually secondary to an origin of the name in the Egyptian word for 'foreskin.' Now all I will have to do is see whether qrnt is preserved in later Egyptian, Coptic and other dialects.
And one more thing ...
It just occurred to me that there is a parallel in the rabbinic literature. The Gemara in Avodah Zarah tells us:
There was once a Caesar who hated the Jews. He asked his advisers, "If someone has dead flesh in his foot, should he cut it off and become healed or should he leave it and suffer?" They answered him, "He should cut it off and become healed." (He was referring to the Jewish people in his empire, whom he saw as a constant source of frustration.) Ketia bar Shalom, one of the advisers, then interjected, "Firstly," he said, "you will never be able to kill all of them, for they are dispersed throughout the four corners of the world ... and they are as important for the continued existence of the world as the winds. (Therefore other monarchs who have a greater appreciation for the indispensability of the Jews in their kingdoms will foil your plans). Furthermore, if you execute all the Jews of your kingdom, your reign will go down in history as a bloody one!
The king responded, "You have argued cogently. However, there is a rule that whoever outwits the king must be put to death. As they were taking Ketia away, a Roman matron called out, "Woe to the ship that travels without paying its dues!" Ketia immediately circumcised himself, exclaiming, "I have paid my dues -- now I may pass through [the Gates of the World to Come] freely!" As they were throwing him to his death he cried out "All my property is granted to Rebbi Akiva and his colleagues!" A heavenly voice was heard saying, "Ketia bar Shalom is destined for the Hereafter!" (Avodah Zarah 10b)
Ketia bar Shalom is not a historical person. He's a mythical figure who personifies the individual who circumcises himself at the very last possible minute of his life. Just look at the text. When the Caesar asked about "cutting off" the dead flesh, the word used is "Yikte'ena" (root: Kata, the same root as that of Ketia). When Ketia objected that killing the Jews would result in a bloody reign, the words he used were "Malchuta Ketia." And the word used to describe his circumcision is "Kat'ah" (root: Kata). The same root from which his name was derived described the problem with which he was faced (Caesar's challenge), his solution to the problem, and his dramatic circumcision, whereby he allegedly merited a share in the Hereafter.
This is all made up. This person never existed.
Just look at Ketia's surname. "Bar," in Aramaic - as in "bar Shalom" - and "ben," in Hebrew, literally mean "son of." However, they are often used in a broader sense, meaning "from" or "of." "Bar Shalom" would mean "son of peace," and indeed Ketia guaranteed the peace of the Jewish people. Furthermore, the story tells us that he acquired for himself eternal peace - "Shalom" - as the hereafter is described in Isaiah 57:2: "He who goes on the straight path [in his lifetime] will attain shalom and will rest in his place of repose."
Ketia bar Shalom is another stock circumcision character.
dating back to conversations with his grandfather, Gaston Frank. "He said we represent one of the last descendants of the Frankist Jewish faith in the world," he muses. "I grew up thinking that our family was something like the Last of the Mohicans."