Eventhough used in Romulus, stirrups weren't used by Etruscan or Latin tribes.
In season 1, the titles form two lines (851 and 853) from Aeneid book VI, when Aeneas speaks with his father Anchises in the Underworld. Anchises reveals him the glorious future that awaits the Roman people, who, according to legends, descended from Aeneas. Here is the translation of both lines: "You, O Roman, govern the nations with your power- remember this! (...) To show mercy to the conquered and to subdue the proud." Great book worth reading.