The period from Passover to the Feast of Weeks is full of sad memories
of massacres of Jews that took place in the days of the Crusades; also
of the miseries that befell the Jews in Palestine in the days of the
Emperor Hadrian. During the month of Iyar, the Jews abstain from
rejoicings and weddings, [120] with the exception of the 18th of the
month, which is the 33rd of the Omer, because, according to Tradition,
a plague that had raged among the disciples of Rabbi Akiba ceased on
that day. The 18th of Iyar, ל״ג בעומר is therefore called “the
scholars’ festival.”