The holiday of Shavuot (Pentecost), which marks the start of the wheat harvest and, according to tradition, the giving of the Torah at Mount Sinai, begins on Thursday night. In 4 BCE, it was the occasion of a Judean revolt against Rome, brought about by the death of the Roman client King Herod a few weeks earlier. Martin Goodman, in a brief examination of Second Temple-era sources about the festival, tells the story:
Crowds who gathered to mark [Herod’s] passing were treated to a feast to mark the end of the seven days of mourning by Archelaus, the son finally designated as his heir, but they took advantage of a mass assembly in the Temple to pour out their grievances, demanding lighter taxes, the release of prisoners put in chains by Herod over many years, and the replacement of the high priest appointed by Herod shortly before his death. . . .
Despite the chaos, Archelaus traveled to Rome to seek confirmation from Augustus but on arrival found himself faced with extensive opposition. As he was delayed in the imperial city, Judaea erupted in unrest, which reached a peak on Shavuot. . . .
Following this incident, Judea rapidly melted into chaos, with violent uprisings all over the country. Rome expected the governor of Syria to intervene when there was serious trouble in Judaea. Publius Quinctilius Varus, the current governor of Syria, accordingly marched south from Antioch with a large army, and he savagely suppressed the uprisings around the kingdom.
Goodman also details how Shavuot was celebrated by an Egyptian-Jewish sect known as the Therapeutae, who welcomed the holiday with a vegetarian feast and then stayed up all night singing hymns and listening to their leaders expound Scripture—a custom strikingly similar to the all-night Shavuot study sessions that originated in the 16th and 17th centuries.
Read more on theTorah.com: https://www.thetorah.com/article/forgotten-shavuot-history-the-4-bce-rebellion-and-the-therapeutae