I'm not very good at memorization. That's one reason why I like to use graphs to put historical and political data into visual form. Here's a rather extreme but superb example of visual history from a website called Maps-of-War. I can't vouch for its accuracy, and it's rather simplified (although I guess that's what you'd expect when you cram 3000 years of history into 90 seconds), but it does seem to agree with what little I know of world religions. Enjoy!