instead of worrying about how many followers you have, pretend that’s what year it is. 1942 followers? congratulations it’s world war II. 306? wow, constantine just became the leader of the roman empire. More than 2014? incredible you’re in the future
What probably started as a civil war between different Jewish groups escalated further and further as the Roman Empire, which Jerusalem was under the jurisdiction of, got h involved.
Causes of the war are disputed, but the results included, most significantly, the destruction of the Second Temple. This meant that Judaism had to be restructured completely - the Temple meant everything to their religion - and resulted in the creation of the modern, rabbinic Judaism.