In addition to /u/Searocksandtrees' comment, this has also been answered here, here, and here. Check out the FAQ here as well.
There's also a thread posted recently about a similar question, [here]https://www.reddit.com/r/AskHistorians/comments/447vdn/as_far_as_im_aware_all_pre_gunpowder_warriors_had/).
Hi! Always room for more discussion, but fyi, there have been some interesting answers on this topic that would be worth checking out. See this post, which includes links to a few more (don't miss those!)