[citation needed] Yoram Bilu, a professor of anthropology and psychology at the Hebrew University of Jerusalem, suggests that there is little or no religious basis for the custom and its popularity is probably mainly social.
Ritual haircut, probably modeled on the Muslim custom of shaving male children's hair in saints' sanctuaries, was practiced by native Israeli Jews (Musta'arbim) as early as the Middle Ages.
Rabbi Isaac Luria Ashkenazi, the 16th-century founder of the celebrated Lurianic School of Kabbalah who assigned special mystical value to the ear-locks, was instrumental in constituting the ritual in its present form.
An obvious problem raised by Avraham Yaari, in an article in Tarbiz 22 (1951), is that many sources cite that Luria held one should not cut one's hair for the entire counting of the Omer, including Lag BaOmer[4] We know from travellers that by the 18th and 19th centuries, the yom hillula at Meron on Lag BaOmer with bonfires and the cutting of children's hair had by then become an affair of the masses.
A well-known Talmud scholar from Bulgaria, Abraham ben Israel Rosanes, wrote that, in his visit to Palestine in 1867, he saw an Ashkenazi Jew giving his son a haircut at the hillula.
"[citation needed] A Hasidic rebbe, Yehudah Leibush Horenstein, who emigrated in the middle of the 19th century, writes that "this haircut, called halaqe, is done by the Sephardim in Jerusalem[clarification needed] at the tomb of Shimon bar Yochai during the summer, but during the winter they take the boy to the synagogue or Beit Midrash and perform the haircut with great celebration and parties, something unknown to the Jews in Europe.
"[citation needed] In Hasidic Judaism, the upsherin marks a boy's entry into the formal educational system and the commencement of Torah study.
Sometimes, they sing a Hebrew song based on the Biblical verse Deuteronomy 33:4: "When Moses charged us with the Teaching / As the heritage of the congregation of Jacob."
It is customary that at the Lag BaOmer celebrations by the tomb of Rabbi Shimon bar Yochai in Meron, Israel, boys are given their first haircuts while their parents distribute wine and sweets.