 Not only was his life almost exactly contemporaneous to that of Johann Sebastian Bach, he was the famous composer's cousin.Walther was most well known as the compiler of the "Musicalisches Lexicon" (Leipzig, 1732), an enormous dictionary of music and musicians.Not only was it the first dictionary of musical terms written in the German language, it was the first to contain both terms and biographical information about composers and performers up to the early 18th century.