R. Mordecai ben Asher Meltzer Klatzko was a Russian rabbi and author; born in Wilna 1797; died in Lida July 2, 1883. He was a descendant of Rabbi Mayer Katzenellenbogen of Padua. R. Klatzko received the usual Talmudical education and soon distinguished himself by his keen mind and retentive memory. He studied under R. Hayyim of Volozhin and married the daughter of R. Loeb Malzer (Melzer), later adopting his surname. After lecturing privately for some time in his native city he was appointed (1831) chief teacher in the newly established yeshivah founded by Mayla. In 1840 he was appointed head of the R. Meilis yeshivah in Vilna, succeeding R. Israel Salanter who had headed it for a short period. In 1844 R. Klatzko was chosen dayyan of Vilna; he retained his positions at the yeshibah and in the rabbinate until 1852, when he was called to Kalvariya, government of Suwalki, to succeed Löb Shapiro of that place, who had become rabbi of Kovno. R. Klatzko remained in Kalvariya till 1864, when he was elected to the rabbinate of Lida, government of Vilna, which position he held until his death. R. Klatzko was considered one of the most eminent rabbis of Russia. He had many pupils, and probably ordained more young rabbis than any of his contemporaries. At an advanced age he became a follower of the hasidic movement and led an ascetic life, devoting much attention to the needs of his fellow men.