The Fall of the Roman Empire (1964) review

Philosopher/ruler Marcus Aurelius (Alec Guinness), who is quite ill, attempts to keep his vast empire thriving despite outside threats from "barbarians" and Persians: he relies on former slave/teacher Timonides (James Mason) for guidance, considers naming Livius (Stephen Boyd) as his successor as opposed to his "son" Commodus (Christopher Plummer) and wants to marry off his daughter Lucilla (Sophia Loren) to the King of Armenia (Omar Sharif) even though her and Livius are in love - after Aurelius is killed by a poisoned apple, Commodus becomes the new Caesar and ruins everything.  Between the lifeless "dramatic scenes" and the cluttered and underwhelming action sequences, it's no surprise this did poorly at the box office (according to the IMDb trivia page, actor Boyd claimed it ruined his career), and only Guinness and Mason stand out among the cast, but visually it's well done, with thousands of extras, sharp costumes and beautiful sets (the production team did splendid work recreating the Roman Forum).  The "truth" of what transpired around 180 A.D. is too complex for a feature film, but this just reduces its demise to a single lunatic, so anyone who'd like an actual history lesson might want to skim a summary of Edward Gibbon's writings on the matter - and while I'm trying to convince you to read, please consider picking up Aurelius' Meditations.