I was so taken with and loved this movie, that I ended up going to see it in the theater 10 times, the first time was when it had already been out for 2 months. I just could not get enough of it. I was so taken with its historical nature, the recreation of the Roman empire, the characters, the music, the costumes, everything about this movie!
There is a fifteen year old series called Rome, which has three years of episodes for free. If you have Amazon Prime. Also look at Anthony Everett’s books and Tom Holland’s as well. There has been so many books on Roman history in the last 30 years it is great.