In his 'short' Masses, Bach created a safe haven for his favourite cantata movements.

The four short Masses that Bach wrote in the 1730s are shrouded in mystery. These ‘Lutheran’ or ‘Short’ Masses are written in Latin, which is unusual for Bach, and they consist of only a Kyrie and a Gloria. What’s more, Bach compiled these Masses almost entirely of material from a small number of sacred cantatas. The Mass in G minor derives its opening from cantata 102, while the other two choruses and three arias are taken from cantatas 187 and 72. Although adjustments had to be made here and there – passages are cut out or added and the key or register is adapted – the chorus from cantata 102 has been transferred more or less intact. The three lines of text derived from Jeremiah fit amazingly well to the tripartite Kyrie-Christe-Kyrie invocation.

It does not seem too far-fetched to presume that Bach wrote these Masses to create a safe haven for some of his favourite pieces. The neutral character of a Latin Mass means it can be used on far more occasions than the one specific moment in the ecclesiastical year assigned to the cantatas written in German.

But why did Bach choose Latin for these Masses? Was he aiming to strengthen his ties with the Catholic king Augustus III in Dresden, who had just come to the throne? In any case, we know for certain that another Mass from this series, the Mass in B minor (which Bach later expanded) was dedicated to Augustus in 1733. With a little delay, Bach was indeed appointed Composer to the Dresden court in 1736. The position lent Bach a status that was to serve him well in his many conflicts with the church council in Leipzig. And with regard to creating a safe haven for his favourite pieces, Bach had also judged well. His Lutheran Masses have withstood the ravages of time, whereas much of his cantata work has been lost.