Complex sentence: He founded the Amsterdam Baroque Orchestra in 1979 and the Amsterdam Baroque Choir in 1992 and has conducted them in recordings and performances of the complete vocal works of Johann Sebastian Bach (started 1994, a project of ten years).
Split into simpler sentences: He founded the Amsterdam Baroque Orchestra in 1979 and the Amsterdam Baroque Choir in 1992. Koopman has conducted them in recordings and performances of the complete vocal works of Johann Sebastian Bach (started 1994, a project of ten years).