Asarah b'Tevet (10th of Tevet), aka Tzom Tevet (Fast of Tevet), is an observance wherein several events collapse into a single day of mournful commemoration. Not all of these actually occurred on the 10th of Tevet, but the dates are near enough to one another (the 8th, 9th, and 10th) to warrant mourning over them all in one fell swoop, on one single day, rather than to have three consecutive days of mourning (i.e. fasting).
The 8th of Tevet, mid-3rd Century BCE
The 8th of Tevet is viewed in Judaism as a dark day in history - the day on which great violence was done to Hashem's Torah. It was on this date that the translation of the five books of Moshe into a pagan tongue (Greek), i.e. the Septuagint, was completed. Note that the Septuagint was only the first five books, not the complete TaNaKh (24 books), at this stage.1 The addition of the Nevi'im and Kethuvim was a later project. The account is recorded very differently in Megillat Taanit and Masekhet Soferim than in the propaganda literature Pseudo-Aristeas.
Next, Masekhet Soferim relays the counter-story from Pseudo-Aristeas (a propaganda tract used to promote the Septuagint) and amends it with a list of the corruptions deliberately made to the Septuagint. Note that in the tract the number of elders is exaggerated from five to seventy-two (marked in green).
Note that by the 2nd century CE, Hellenized Jews had rejected the Septuagint version in favor of alternative Greek translations, i.e. those rendered by Aquila (a convert - possibly Onkelos; early 2nd-century), Theodotion (a Hellenized Jew, mid-2nd century), and Symmachus (a Samaritan convert; late-2nd century).2 Renowned Jewish scholar Emanuel Tov asserts that the Jewish rejection of the Septuagint was actually much sooner, before the fall of the Second Temple, and even sooner than that - before the inception of the Christian sect:3
Jews already began to see the LXX [Septuagint] as problematic in the pre-Christian period.…With the advent of Christianity in the first century C.E., the LXX, which began as the biblical text for Greek speaking Hellenistic Jews, was accepted as holy writ by this new group of early Christians, and was concomitantly dropped by other Greek-speaking Jews and ceased to be considered authoritative scripture by them. Around the same time, the Samaritans adopted the version of the Torah known as the Samaritan Pentateuch, and the Qumran community that had assembled texts of different types ceased to exist.
The Sages of did not permit any books outside the Torah to be rendered into Greek, so the addition of the Nevi'im and Kethuvim to the Septuagint would have put the entire product into disfavor among the Jewish community.
Another of the stated reasons for Jewish rejection is that the Septuagint, which had thirteen intentional corruptions from the very start, had become further corrupted with Christian alterations during the 1st century. This seems to be what prompted the creation of new Jewish translations into Greek in the 2nd century. Tehillim 14:3 is an oft-cited example of early Christian tampering - altered to match Romans 3:10-18 of the Christian epistles (though Christian sources insist that this proves the opposite, i.e. that the Septuagint was quoted by the New Testament writers as "the Bible of the Apostles").
Where the Greek text of LXX 13:3 (=MT 14:3) has χρηστότητα (honesty) as its rendering for the Hebrew ט֑וֹב (good), the parallel passage at Tehillim 53:4 (LXX 52:3) has the more appropriately-translated term ἀγαθόν (good) instead.
There is no evidence of any Hebrew version of Tehillim 14:3 which has the expanded text presented above. Only in the Greek of Romans 3:10-18 do we see the text arranged as it is in the accepted text of the Septuagint. Nota bene: The passage as laid out in Romans is what is called a "string of pearls" - a liturgical weaving together of several verses with a common theme, in this case Tehillim 14:3 (the proper text) has added to it Qohelet 7:20, Tehillim 53:2b-3, 5:9b, 140:3b, 10:7; Isaiah 59:7-8a; and Tehillim 36:1b.
The 9th of Tevet, ca. 5th Century BCE
Ezkera Matzok, Selichot Addition to Shacharit Service (Joseph ben Samuel, 1050)
‘I remember the distress which befell me; three blows He inflicted on me in this month… on the 8th day… the Greek King compelled me to translate the Law (Torah) into Greek… on the 9th, Ezra the scribe, was forcibly torn away… on the 10th (the day when the Babylonian enemy began to lay siege to Jerusalem prior to the destruction of the First Temple) the son of Buzi (Ezekiel) was commanded to record in the book of prophecy the date of this very day as a memorial for a despised and decaying people
The 10th of Tevet, 70 CE
The final cause for our mourning on this day is the Siege of Jerusalem in 70 CE. This is recorded in far more places than the other two events - the TaNaKh, the Talmud, and Josephus among them.
Since the Jews of Jerusalem could not understand Greek, Josephus was employed by his Roman friend Titus, leader of the Siege, to translate for him - marking him as a traitor against his people in Jewish memory. The original Aramaic text of Josephus's works is no longer extant, thus it is presented below in Greek as the oldest form available to us.
יוסף בן מתתיהו, מלחמות היהודים, ו':ב':א'
(α) ... ὁ Ἰώσηπος, ὡς ἂν εἴη μὴ τῷ Ἰωάννῃ μόνον ἀλλὰ καὶ τοῖς πολλοῖς ἐν ἐπηκόῳ, τά τε τοῦ Καίσαρος διήγγελλεν ἑβραίζων.
Josephus, Jewish Wars 6:2:1
(1) ... Josephus stood in such a place where he might be heard, not by John only, but by many more; and then declared to them what Cæsar had given him in charge: and this in the Hebrew language.
Yom haKaddish haKlali, 1951
Since 1951, the Tenth of Tevet has also been marked as a General Kaddish Day (Yom HaKaddish haKlali) in Israel to mourn the 6 million Jewish victims of the Holocaust. The Mourner's Kaddish (an Aramaic prayer for the deceased dating to the time of Ezra) is recited on this day for people whose date or place of death during the Holocaust is still unknown.
- Emanuel Tov, The Text-Critical Use of the Septuagint in Biblical Research (Winona Lake, Ind.: Eisenbrauns, 2015), 16.
- Origen, Hexapla (3rd century).
- Emanuel Tov, "The Bible and the Masoretic Text," TheTorah.com (10 parts; online: https://www.thetorah.com/article/the-bible-and-the-masoretic-text).