Welcome to the penultimate episode of the season! According to Wikipedia, The Well-Tempered Clavier is a pair of collections solo clavier (a generic term for keyboard instruments at the time) music, each of which contains a prelude and fugue in each major and minor key. You can listen to the entire series here. Spoilers below!
Also, let’s get a quick tally to see how many time periods everyone thinks we’re working with. For consistency, let’s define a “time period” as a period of time that a character believes they are currently experiencing (i.e., hosts who think they’re in the past count; humans narrating history do not).