The crisis started from within. Josephus records that after the High Priest Onias III died, a power struggle erupted between his brothers. Jason and Menelaus each bribed the Seleucid king for the priesthood. Menelaus won, and his supporters—including the sons of the Tobiad family—went further than anyone expected. They asked Antiochus IV for permission to build a Greek gymnasium in Jerusalem. Then they surgically reversed their circumcisions so they could exercise naked without being identified as Jews. They abandoned every ancestral custom.
Antiochus used their invitation as a foothold. On his return from a failed Egyptian campaign—the Romans had humiliated him and forced his retreat—he turned his frustration on Jerusalem. In the 143rd year of the Seleucid era, he took the city without a fight, because the Hellenizing faction opened the gates for him. He slaughtered the opposition and plundered the Temple treasury.
Two years later he returned and stripped the Temple bare: the golden menorah, the altar of incense, the table of showbread, even the fine linen curtains. He killed thousands, enslaved ten thousand more, and burned the finest buildings. He built a military citadel in the lower city overlooking the Temple Mount, garrisoned it with soldiers, and turned it into a permanent weapon against Jewish worship.
Then came the decrees. Antiochus outlawed Torah observance entirely. No Shabbat (the Sabbath). No circumcision. No sacrifices. He erected a pagan altar on top of the altar of God and sacrificed swine on it. Women who circumcised their sons were thrown from the city walls with their infants tied around their necks. Josephus notes that "many Jews, out of a voluntary compliance, polluted themselves"—choosing assimilation over death. The Samaritans sent a letter to Antiochus renouncing any connection to the Jews, and their temple at Mount Gerizim was renamed for Zeus. The darkest hour had arrived.