Complex sentence: This third is the earliest, longest, and most musically complex of the six, and was written in Leipzig in 1723 for the funeral (on 18 July 1723) of Johanna Maria Käsin, the wife of that city's postmaster.
Split into simpler sentences: This third is the earliest of the ones written at Leipzig, and the longest and most musically complex of the set. It was written in Leipzig in 1723 for the funeral (on 18 July 1723) of Johanna Maria Käsin, the wife of that city's postmaster.