The Fast of the 10th of Tevet is actually a compilation of three sad & tragic historical events over the course of three days.
On 8 Tevet – The Septuagint was published.
On 9 Tevet – Ezra the Scribe passed away
On 10 Tevet – The siege on Jerusalem began
Once upon a time, all three days were observed as fast days but the rabbis merged them into one day on the most tragic event – the siege on Jerusalem because it was too much for the Jewish people to fast three days in a row (the fast is a daytime fast only and one can eat at nightfall).
Historical reasons for each of the days of mourning:
8 Tevet – In the third century BCE, Ptolemy II, Greek ruler in Alexandria, Egypt ordered 70 Jewish elders to translate the Torah to Greek. He put each one