I can't believe no one has commented on this excellent British miniseries yet! I saw it when it was first shown in America in the mid/late 70's. Super interesting, even if a bit soapy. Lots of humor. The acting's fantastic and there are a lot of well-known faces (including Star Trek:TNG's Captain Picard, Patrick Stewart, as Sejanus -- with hair!). A real treat. Enjoy -- then read the fun (if not exactly accurate, according to my college history professor) Robert Graves books on which it's based. You'll love both film and book.
Lots of poisonings, lots of secrets, lots of backstabbing, lots of sex. Very witty in presenting the human condition and a peek into what life in Rome around the time of Christ may have been like.