1. Allegro 2. Adagio 3. Allegro (https://www.youtube.com/watch?v=Kpqm1hxgH-w)
Bach was the first composer to develop the concerto for a keyboard instrument. Bach’s surviving works allow us to trace this development to three distinct phases.
Firstly in 1721 during his work as Court Cappelmeister at Cöthen, he composed Brandenburg Concerto No.5 (https://www.youtube.com/watch?v=yTY8Kb96wGk), which features a solo harpsichord part alongside violin and flute soloists. The virtuoso first movement cadenza is for keyboard alone and the continuo bass is eliminated from the slow movement. It could be argued that Bach established the standard for the modern keyboard concerto with this work alone.
Next in 1726, while composing Cantatas in Leipzig as Kantor of the St Thomas School, he reworked a number of instrumental concerto movements as cantata sinfonias and choral movements featuring solo organ. The first and second movements of the Concerto in D Minor are used in Wir müssen durch viel Trübsal BWV 146 (https://www.youtube.com/watch?v=5nbn5g9vfSk) and the last movement in Ich habe meine Zuversicht BWV 188.(https://www.youtube.com/watch?v=B1R03pRtkT8)
Finally, during his work as Director of the Leipzig Collegium Musicum in the 1730’s, he arranged a series of at least eight solo keyboard concertos from instrumental concertos he had previously composed in Cöthen. In fact all of Bach’s Keyboard Concertos seem to have been derived from earlier works with the exception of the Concerto for Two Harpsichords BWV 1061(https://www.youtube.com/watch?v=aLCPyP054WA).
The surviving manuscripts show Bach spent much time developing the left hand of the keyboard parts. In particular, the left hand rarely merely doubles the continuo bass, thus giving the keyboard more independence as a solo instrument.
The concerto in D Minor is presumed to have been produced from a lost violin concerto from the Cöthen period (reconstructed here: https://www.youtube.com/watch?v=-WDqTc20jxw). Bach seems to have particularly liked the work, using its material to fashion cantata movements as previously mentioned and in 1734 lending it to his son Carl Phillip Emanuel who turned it into a keyboard concerto. Finally around 1738 he refined the work of his son, producing the work as it is known today.