Thomas exhibited a prodigious musical talent, and at the age of seven he played the violin for the King of Hannover. In 1845 his family moved to New York, and in 1854 he secured a position in the first violin section of the New York Philharmonic Society, and the following year he helped to launch a series of monthly chamber concerts in the city, which lasted for fourteen years. In 1859 he made his debut as a conductor, and formed his own orchestra in 1862. He held conducting posts in Philadelphia (1876), Brooklyn (1862–78), New York (1877–91), Cincinnati (1878–79), and Chicago (1891–1905).
Correspondence with Tchaikovsky
Two letters from Tchaikovsky to Theodore Thomas have survived, both dating from 1892, and have been translated into English on this website: