- Birnbaum, Nathan (Acher, Mattathias)
- (1864-1937)Austrian political philosopher. He was born in Vienna. An advocate of Jewish nationalism, he co-operated with Theodor Herzl and served as general secretary of the World Zionist Organization. However after the Third Zionist Congress in 1899, he became an opponent of the Zionist movement. He regarded cultural and political autonomy in the diaspora as the means of attaining Jewish national existence. He was a convenor of the conference at Czernowitz in 1908 which proclaimed Yiddish as a national language. Later he embraced Orthodoxy.
Dictionary of Jewish Biography. Dan Cohn-Sherbok.