He finished these three works within six weeks during the summer of 1788, a remarkable feat even for him.
The major instrumental works of this period bring together all the fields of Mozart's earlier activity and some new ones: six symphonies, including the famous last three: no. 39 in E-flat Major, no. 40 in G Minor, and no. 41 in C Major (the Jupiter —a title unknown to Mozart). He finished these three works within six weeks during the summer of 1788, a remarkable feat even for him.