Related Clues:
- Periods often named for rulers
- Spans with names
- Important periods of history
- Pleistocene and Holocene, for two
- Special periods
- Eventful spans
- "-zoic" time periods
- Baroque and Romantic, for classical music
- Baseball's dead-ball and live-ball
- Times to study?
- Prohibition and Big Band
- Periods named for football coaches, perhaps
- Time spans named for presidents
- Eon makeup
- Presidential terms, to historians