I had actually given some prior thought to this issue because the the show Outlander. One of the characters goes back to 1743 Scotland from the 1960s with the intention of changing the outcome of the Battle of Culloden. However she takes no useful items or knowledge to accomplish this goal. I looked into it and dynamite can be made with a few chemical items that were easily obtainable in the 1700s (or 1500s) and their use revolutionised warfare.