Johann Sebastian Bach worked at the ducal court in Weimar from 1708 to 1717. The composition of cantatas for the Schlosskirche (court chapel) on a regular monthly basis started with his promotion to Konzertmeister in March 1714.
Church cantatas
From 1714 to 1717 Bach was commissioned to compose one church cantata a month. His goal was to compose a complete set of cantatas for the liturgical year within four years. In the course of almost four years there he thus covered most occasions of the liturgical year.
The expression "Weimar cycle" has been used for the cantatas composed in Weimar from 1714 (which form the bulk of extant cantatas composed before Bach's Leipzig time).
Cantatas 54 and 199 were performed within the cycle but possibly composed earlier. BWV 18 and 21 may also have been composed before 1714.
Other sacred music and cantatas of Bach's Weimar period
In the Bach-Jahrbuch of 2015, Peter Wollny wrote that Bach likely encountered several of the old-school contrapuntal sacred compositions, which were going to play a seminal role in the composer's output of the 1740s, for the first time in Weimar. Among these compositions are,