You can find actor's names for just about any movie at www.IMDB.com They don't always have pictures of every actor, but they usually have the main characters.
Here's the latest versions of those two titles, if you do a search for the movie title you'll get the older ones;
I think the actor you refer to is Brian Cox (although I can't find any credit for him in 'Gladiator'). Brian was the original Hannibal Lecter as he played the role in Manhunter (based on Thomas Harris's 'Red Dragon') in 1986. The chief protagonist was played by William Petersen of CSI fame.