His last word was Livius.
2 seconds sound clip from the The Fall of the Roman Empire (1964) movie soundboard.
You can hear this line at 01:12:42.222 in the Blu-ray version of the movie.
Quote context
[...]
- How can you ask me to forget everything that I am? All that my life means.
- How can your life mean anything without love? I will not let this happen.
- Father, why did you deny me?
- You are looking for a document, Timonides? A document in which my father named me his heir.
- I will bare witness that it was Caesar's wish, that you'd be his heir.
- If it was only your word, Lucilla, there would be doubt.
- Caesar must be undoubted Caesar.
- Is it not possible, Lucilla, that there are other ways of becoming the real heir of Marcus Aurelius?
[...]