Passing of Rabbi Menachem Mendel of Kotzk (1787-1859), renowned Chassidic leader, and forerunner of the "Ger" Chassidic dynasty.

Rebbetzin Chaya Mushkah Schneerson (b. 1901), wife of the Lubavitcher Rebbe, passed away on the 22nd of Shevat of the year 5748 (1988). For more on the Rebbetzin, see link below. Chabad's annual international conference of sheluchot (woman "emissaries") is held on or near this date.

Links: An on-line biography; more on the Rebbetzin