Alternatively, a date as late as the 1750s has been suggested. To a large extent, the piece conforms to the characteristics deemed typical of the north German organ school of the Baroque era with divergent stylistic influences, such as south German characteristics. The third is a compilation of the Brandenburg concertos. The Brandenburg Concertos by Johann Sebastian Bach (BWV 1046–1051, original title: Six Concerts à plusieurs instruments) are a collection of six instrumental works presented by Bach to Christian Ludwig, Margrave of Brandenburg-Schwedt, in 1721 (though probably composed earlier). They are widely regarded as some of the best orchestral compositions of the Baroque era. The fourth is an unlikely quartet for harpsichords and orchestra. This is one in A Minor BWV1065 – one of seven complete concertos.