In the "third cycle" period Bach also performed many cantatas composed by his second cousin Johann Ludwig Bach a Leipzig premiere. For the period from Purification, to Trinity XIII, there are extant copies by Johann Sebastian Bach and his usual scribes for 16 cantatas (JLB 1–16), covering nearly half of the occasions in that period. Another cantata, JLB 21, was likely also given its Leipzig premiere in this same period (Easter, ), but was for some time misattributed to Johann Sebastian Bach as his cantata BWV 15.