sentences:  The earliest organ concertos can probably be credited to Handel (16 concertos, c. 1735–51), the earliest harpsichord concertos to Johann Sebastian Bach (14 concertos for one to four harpsichords, c. 1735–40).In the latter case, all but probably one of the concertos are arrangements of existing works, though Bach had already approached the idea of a harpsichord concerto before 1721 in the Brandenburg Concerto no.5.