Four short masses, written for a Bohemian count in 1738/9 by an older Bach. They’re so called parodies, they use elements of earlier work in a new context. Maybe Bach wanted to put them in a less time sensitive order (they were linked to the liturgical year), or maybe he just wanted to collect some money by reusing some old successes.
These works are collectively known as Missae breves, but also as the Lutheran Masses, or as Kyrie-Gloria Masses. The last name because they all consist of two first movements from parts of a mass: the Kyrie and the Gloria. These two are then followed by four more freeform choral parts with very different names.
This is quite a beautiful recording, worth your consideration if you can find it. I must say that Philips really did good work with this ‘Living Baroque’ series. There are a lot more of these, but not in my possession. If I can find them, I might buy some more.