The Burning of the Torah Scroll by ApustamusThe Gemara tells us that we know this event happened on the seventeenth of Tamuz as a tradition from our forefathers. The Gemara does not tell us who Apustamus was, or what the significance of the Torah scroll was.
The R"av writes that Apustamus was a Greek officer at the time of the second Temple. The Tiferet Yisroel offers two possible explanations as to the significance of the scroll. One is that this scroll was the one written by Ezra HaSofer, Ezra the Scribe. The text was the most authoritative, and all other Torah scrolls that were written were checked against this one for accuracy and errors. Another understanding is that he burnt every Torah scroll he could find.
No matter the explanation, the intent behind Apostamus’ actions remain the same: to eradicate Torah from the nation of Yisrael.
The Gemara tells us that we know from the verse in Daniel 12:11 that this event occurred on the 17th of Tamuz, as the verse says that "on the day the Tamid offering ceased to be brought, an idolatrous image was placed in the Temple." Although the Gemara here does not mention who placed the idol in the Temple, the Gemara in the Talmud Yerushalmi mentions that there is debate as to who did it. Some say that Apustamus placed the idol in the Temple as well as burning the Torah scroll. Others say it was placed by Menashe, an evil Jewish king, in the time of the first Temple. (Torah.org)
The Placing of an Idol in the Sanctuary
[Since the 17th of Tammuz fell on Shabbat, the fast was postponed until today, Sunday July 24th.]
17th of Tammuz: Breaking of the Luchot
17th of Tammuz: The Discontinuance of the Tamid
17th of Tammuz: The Breaching of the Wall Around Yerushalayim