Caligula and Napoleon: Abbr., 4 letters
Dominions: Abbr., 4 letters
HRE and Byz., e.g., 4 letters
Little Caesars? (Abbr.), 4 letters
Montezuma II, Hirohito, et al., 4 letters
Napoleon I and III, e.g., 4 letters
Nero and Napoleon (abbr.), 4 letters
Nero and Napoleon, briefly, 4 letters
Realms (Abbr.), 4 letters
Roman and Holy Roman: abbr., 4 letters
Royal ruler: Abbr., 4 letters
Royals: Abbr., 4 letters
Supreme rulers: abbr., 4 letters