Short answers, pulled from the story.
Otto Jahn (1813-1869) was a German archaeologist, philologist, and writer on art and music. He is best known for his scholarly biography of Wolfgang Amadeus Mozart, published in 1856, which the 11th edition of the Encyclopaedia Britannica described as a work of extraordinary labour and of great importance for the history of music.
Jahn was dismissed from Leipzig in 1851 because he had participated in the political movements of 1848-1849. He was dismissed alongside the historian Theodor Mommsen and the philologist Moritz Haupt.
Jahn's biography of Wolfgang Amadeus Mozart appeared in 1856, the centenary year of Mozart's birth. An English translation by P. D. Townsend was published in 1891, and the work has been revised by Hermann Abert and Cliff Eisen and continues in use today.
From 1852 onward, Jahn collected Mozart manuscripts and letters and copied many others. When he learned that Ludwig von Köchel was compiling a Mozart catalogue, he turned all of his collected material over to Köchel.
Jahn held posts at the University of Greifswald (from 1842, becoming ordinary professor in 1845), the University of Leipzig (from 1847 until his dismissal in 1851), and the University of Bonn (from 1855), where he was also director of the academic art museum.
Hugo Blümner, the classical archaeologist and philologist, was among Jahn's most notable students.