It's amazing that many years ago people were already betting on the fights that existed, today we have boxing, MMA and so many fighting sports, but at that time people liked fights to the death, it was a more violent version of MMA so I mean, I'm basing myself on movies and series that portrayed history from many years ago, I wonder what people addicted to gambling were like back then? What would they do to support their addiction? This is something I ask myself, because today there are many things that people take and sell to support their addiction, but in the many years ago what did they do?
Well good to know all of these, I did not know about the gambling history but I have heard once in the Bible that there is gambling before ancient days. As OP said --it was Before Christ [BC], so it means gambling has existed in different countries but it has the same feature or it has the same name. The gambling industry as of now has a large population, even in the online gambling business, we saw almost a week there are new gambling websites appearing. Perhaps they saw how truly profitable the gambling business is.
However, thank you for sharing this OP and your effort searching all of these.
In movies that portray old things you can see fights and people betting