Counting the Omer is a strange commandment: a spoken number, once a night, for forty-nine nights, with a blessing, and if you miss a whole night you continue without the blessing for the rest of the season. It links the exodus to the revelation and originally counted a barley harvest. Somewhere in the Geonic period the period acquired a mourning character — the Talmud attributes it to a plague that killed twenty-four thousand of Rabbi Akiva's students because they did not treat one another with respect, and historians generally read the plague as a euphemism for the Bar Kochba revolt. So there are no weddings, no haircuts and no live music for most of the period, with communities differing about which weeks. On the thirty-third day the restrictions lift, and Lag BaOmer became a Hasidic and Sephardi festival centred on Rabbi Shimon bar Yochai, the Zohar's attributed author, whose tomb at Meron draws hundreds of thousands overnight for bonfires and the upsherin, a boy's first haircut at three. In 2021 a crowd crush in a narrow exit passage at Meron killed forty-five people and injured more than a hundred and fifty. The state commission of inquiry found long-standing failures of authority over the site, which had been divided between competing religious bodies for decades, and the argument about who controls Meron is not settled.