Albert Wilhelm Karl Niemann (15 January 1831 – 13 January 1917) was a leading German tenor opera singer especially associated with the operas of Richard Wagner. He gave important premieres in France, Germany, England and the United States, and played Siegmund in the first complete production of Der Ring des Nibelungen (Bayreuth Festspielhaus 1876).
Born in Erxleben, near Magdeburg, Niemann lost his father (an innkeeper) at an early age and was brought up by his mother, a woman 'of almost unwomanly hardness' who lived to be ninety. He was apprenticed to an engine-maker, but ran away to Dresden to make his own life. He grew up with a Germanic dedication to hunting but also student-like, reading extensively in science, history and philosophy. He was not particularly sociable or tactful, was blunt in speech and often boorish in behaviour.
Niemann made a debut in Dessau in 1849, singing in minor roles and in chorus. He received training from Fritz Schneider (director of the ducal Hofkapell), from Albert Nusch and from Gilbert Duprez in Paris. Until 1866 he had various engagements in Stuttgart, Königsberg, Stettin, and from 1854 in Hannover. At Hannover he sang Tannhäuser (from 1854), Lohengrin (from 1855) and Rienzi (from 1859).
He had a large physique and a large voice to match. In 1859 he married the soprano Marie Seebach: however it is said that this marriage ended in divorce after he threw her out of a first-floor window.
Niemann visited Wagner in the Asyl, at the composer's invitation, in summer 1858. Wagner had him in mind to create the role of Siegfried. From 1859, Wagner had involved Niemann (then at Hanover) in his plan to form a model German company to perform some operas, including Tristan und Isolde, in Paris in 1860. The plan was for Niemann to sing Tannhäuser and Josef Tichatschek to sing Lohengrin, alternating to rest their voices and able to replace each other if needed, and both to share a production of Tristan und Isolde as well. However, the projected Isolde, Frau Bürde-Ney, could not be released from a Leipzig contract, and the project foundered.