It is believed that Vivaldi began his flute works in the late 1720's, after Johann Joachim Quantz's tour. This concerto un particular resorts to the fast-slow-fast movement structure, makes use of the ritornello form and has a lighthearted temperament. Of the nearly 50 concertos that he wrote for two soloists and orchestra, this is the only one for two flutes.

Reference : https://musopen.org/music/784/antonio-vivaldi/concerto-for-2-flutes-in-c-major-rv-533/