The first series covers Medieval chant and organum through to Bach's cantatas and passions. It's great to watch for the music alone! There's also a second series which covers later music, which is on my to-watch list.
We're really enjoying our documentaries at the moment. :)
Episode 1: The Gothic Revolution
Episode 2: Palestrina and the Popes
Episode 3: Byrd & Tallis: Singing the Lord's song in a strange land
Episode 4: Bach and the Lutheran Legacy