I found a page that lists inventions between Years : 1 AD to 1,000 AD. Then I simply looked at all things before and up to...500 ad, you see I really wanted to know what was going in the world at those time, take a look at the lists
http://www.krysstal.... AD to 1,000 AD
I was most surprised, unless I have some sort of mental; block on understanding what AD really is?
This one is impressive for it's time as well. LINK - Hierapolis Sawmill