- Baba Yetu, which has become a Leitmotif for the entire series.
- The Warlords expansion theme also counts.
- The Brandenburg Concerti played during the Renaissance era also qualify, though they're not original to the series.
- Most of the background music in Civ IV is this way. It's been described as "one of the few games that lets you change the background music, and one of the few games where you don't need to".