German rabbi and teacher; born at Bleicherode June 14, 1814. In 1834 he was called as teacher to Sondershausen, where he worked under I. Wolffson, whom he succeeded in 1837 as principal and preacher. In 1840 he was appointed teacher at the "Realschule," where he taught (1840-86) mathematics, geography, German, Latin, and history.
In 1845, having received his rabbinical diploma from Rabbi Löb Blaschke in Schönlanke and from Rabbis J. J. Oettinger and Michael Sachs in Berlin, he was appointed "Landesrabbiner" of the principality of Schwarzburg-Sondershausen; and shortly afterward the few scattered Jewish communities in the principality of Schwarzburg-Rudolstadt were added to his jurisdiction.
In 1848 he attended the conference of German teachers held in Eisenach, and was elected one of its officers. It was due to his initiative that in the first section of the constitution, which originally read, "The foundation of all education is Christian," the word "Christian" was changed to "moral and religious" ("sittlich-religiös"). Four hundred members voted in favor of the amendment, proposed by Heidenheim; and this so embittered a missionary who was present that he exclaimed: "We have sold Christ to the Jews." The liberal tendency of the time appears also from the fact that this gathering took place on Rosh ha-Shanah (New-Year's Day), and that the Jewish community granted to its rabbi leave of absence for the occasion. At Passover, 1902, Heidenheim celebrated the sixty-fifth anniversary of his inaugural sermon.
- Allg. Zeit. des Jud. 1877, p. 666; 1878, p. 294; 1879, p. 651; 1881, pp. 746 et seq.