Tonight is the Yarzheit of the Holy MaHaRaL

Reb Yehuda Loew, the Maharal, 1609 (great grandfather of Alter Rebbe) , Reb Yehuda Loew, the Maharal (1525-1609).
From Yarzheit.com

Born in Posen, Poland, on the night of the Pesach Seder, to a distinguished family of rabbis that traced its ancestry to King David. He was the youngest of four brothers. The Maharal married at the age of 32 to Pearl. He had six girls and one boy who was named after the Maharal's father, Beztalel. In 1553 he was elected rabbi of Nikolsburg and the Province of Moravia, where he remained for the following 20 years. In 1573 he moved to Prague, where he opened a yeshiva. In 1592 the Maharal accepted the position of rabbi in Posen, returning to Prague in 1598 to serve as its chief rabbi. The Maharal castigated the educational methods of his day where boys were taught at a very young age and insisted that children must be taught in accordance with their intellectual maturity. One of his leading disciples was Reb Yom Tov Heller, author of the classic mishnaic commentary, Tosafos Yom Tov, who, in his introduction informs us that the Maharal greatly encouraged group study of the Mishna. At the same time, he was fully conversant with the scientific knowledge of his time as well as friendly with some of the contemporary eminent scientists. His disciple, Dovid Ganz, worked in the observatory of Tycho Brahe, the distinguished astronomer. He was a prolific writer, and his works include: Tiferes Yisrael on the greatness of Torah and mitzvos; Netivos Olam, on ethics; Be'er Hagolah, a commentary on rabbinic sayings; Netzach Yisrael, on exile and redemption; Or Chadash, on the book of Esther; Ner Mitzvah, on Chanukah; Gevuros Hashem, on the Exodus; and many others. He was held in great esteem by his contemporaries and has had a profound impact on all streams of Judaism. Rabbi Kook stated that the "Maharal was the father of the approach of the Gaon of Vilna on the one hand, and of the father of Chasidus, on the other hand." He has been described as a Kabbalist who wrote in philosophic garb.

Me: He is also well known for creating the Golem