The Boston Symphony Orchestra (BSO) is an American orchestra based in Boston, Massachusetts. It is one of the five major American symphony orchestras commonly referred to as the "Big Five". Founded in 1881, the BSO plays most of its concerts at Bostons Symphony Hall and in the summer performs at Tanglewood. Andris Nelsons is the current music director of the BSO. Bernard Haitink currently holds the title of conductor emeritus of the BSO, and Seiji Ozawa has the title of BSO music director laureate. The BSO was founded in 1881 by Henry Lee Higginson. Its first conductor was George Henschel, who was a noted baritone as well as conductor, and a close friend of Johannes Brahms. For the orchestra, Henschel devised innovative orchestral seating charts and sent them to Brahms, who replied approvingly and commented on the issues raised by horn and viola sections in a letter of mid-November 1881.