hi! not discouraging more responses, but stirrups are a popular topic here; get started on these:

• Where were stirrups first invented and widely used? And why did it take so long? - Ancient China

• Roman Legions v. Stirrup Equipped Heavy Cavalry - Ancient China

• How important were stirrups to mounted warfare? What, other than stirrups, could have led to the rise of shock cavalry? - Ancient Greece, Ancient Rome, Franks

• Why did it take so long to invent the stirrup? - Ancient Rome

• Why were the Romans able to field such huge armies? Why weren't these numbers matched again until the mid-18th century, despite advancing technology and rising populations? - Ancient Rome

• Historians of Reddit: what historical facts do you think are exaggerated or downplayed that could change the way people think about a certain historical event? (x-post from "askreddit") - various

• Just how effective and were slings as weapons in ancient warfare and how were they used? - various

• Battle of Hastings and Stirrups - Battle of Hastings

• How did heavy cavalry lancers work? - Battle of Hastings