I just have to say...74 gladiators to start off with, thats not a lot when you think about what he did, I mean he gathered an army of over 100,000 in a few years, and it all started off with those gladiators...
Anyway, I heard that the figure was 72 from one book, but I can't remember what the name was. But it is true that most round the numbers to something like 70.