Yitzchak Blazer
Yitzchak Blazer was an early important leader of the Musar movement.
He is also sometimes referred to as Rabbi Itzele Peterburger due to his position as Chief Rabbi of St. Petersburg at a time when it was the capital of Russia. he married the mother of the Lomza Rav, Rabbi Moshe Shatskesz when his father was niftar becoming the stepfather of Rabbi Moshe Shatzkes.
Background
Blazer was a student of Rabbi Yisroel Salanter, founder of the Musar movement, under whose direction he was appointed Chief Rabbi of St. Petersburg at the age of 25.Career
Among Blazer's accomplishments, in addition to his own authorship of Pri Yitzchak, a halakhic responsa text, was the publishing of many of Salanter's letters in Or Yisrael, as well as articles on Musar, Teshuvah, and the life of his teacher, Rabbi Yisrael Salanter. He also authored Kochvei Ohr.From 1880 to approximately 1891, he served as the head of the Kovno Kollel in Kaunas, Lithuania, which was founded by Salanter. Under Blazer's direction, the kollel came to be "considered by its contemporaries as a bastion of the Mussar movement," a Jewish ethical movement based in Lithuania within the Russian Empire, and was attacked by the Musar movement's opponents.
He later joined Nosson Tzvi Finkel in leading the Slabodka Yeshiva.
Rabbi Yosef Yozel Horwitz was one of the primary pupils of Rabbi Blazer.