Lag BaOmer (, LaG Bāʿōmer), also Lag B'Omer or Lag LaOmer, is a Jewish religious holiday celebrated on the 33rd day of the Counting of the Omer, which occurs on the 18th day of the Hebrew month of Iyar. According to some Rishonim, it is the day on which the plague that killed Rabbi Akiva's 24,000 disciples came to an end, and for this reason the mourning period of Sefirat HaOmer concludes on Lag BaOmer in many communities. According to modern kabbalistic tradition, this day is the Celebration of Simeon ben Yochai and/or the anniversary of his death. According to a late medieval tradition, Simeon ben Yochai is buried in Meron, and this association has spawned several well-known customs and practices on Lag BaOmer, including the lighting of bonfires and pilgrimages to Meron. Additionally, in modern-day Israel, the holiday also serves to commemorate the Bar Kokhba Revolt against the Romans. Etymology Lag BaOmer is Hebrew for "33rd [day] in the Omer". (The Hebrew letter ל (lamed) or "L" has the numerical value of 30 and ג (gimmel) or "G" has the numerical value of 3. A vowel sound is conventionally added for pronunciation purposes.) Some Jews call this holiday Lag LaOmer, which means "33rd [day] of the Omer", as opposed to Lag BaOmer, "33rd [day] in the Omer". Lag BaOmer is the traditional method of counting by some Ashkenazi and Hasidic Jews; Lag LaOmer is the count used by Sephardi Jews. Lag LaOmer is also the name used by Yosef Karo, who was a Sepharadi, in his Shulchan Aruch (Orach Chaim 493:2, and cf. 489:1 where BaOmer is inserted by a glossator). (The form Lag B'Omer ["33rd day of an Omer"] is also sometimes used, though it is not grammatically correct in this setting.) The Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, writes in his Likkutei Sichos that a deeper reason for the term Lag BaOmer is that the Hebrew words Lag BaOmer (ל״ג בעמר, spelled without the "vav"), have the same as Moshe (משה, Moses). He writes that Rabbi Shimon bar Yochai, whose yahrzeit is traditionally observed on this day, was mystically a spark of the soul of Moses. Origins The origins of Lag BaOmer as a minor festival are unclear. The earliest clear reference to the observance of Lag BaOmer is a brief statement by Isaac ben Dorbolo (12th century, northern France). It is found in his annotations to