Dan Carlin mentions in 'Hardcore History: King of Kings 1' that there are ancient egyptian figurines where one has a guy sitting on a horse's rump, attempting to ride it, "as if they hadn't figured out the proper way to ride a horse; stuff that would be obvious to us today".
Someone in a youtube comment mentioned to me that people rode horses in the bronze age. But I also heard from Dan that cavalry first appeared in 1000 BC, which is a little ways after the bronze age.
I learned from lindybeige in one of his videos (I think the one on light chariots?) that cavalry had to be bred large enough to to ride, and couldn't be ridden in the bronze age.
The information together is a bit cloudy, so could someone with good sources help me clear up the current view of the origin of cavalry? I'll even give you a thumbs up. :P
Horses may have been ridden as early as 4000 BC in the Eurasian steppe.^1 The first confirmed image of a person riding a horse in the Near East dates to around 2000 BC.^2 Horses were ridden in the Late Bronze Age: there are depictions of men on horseback in military situations in both Egyptian and Hittite art. Rather than fighting as cavalry, these are believed to have operated as scouts or messengers.^3 Late Bronze Age Greece also gives us depictions of mounted men, with a rider figurine from a burial at Koukounaries on Paros, and a depiction of an armed rider on a painted vase from Mouliana on Crete.^4 Such riders did not necessarily fight as “cavalry” but may have dismounted for combat, like more recent dragoons.
True cavalry is an Iron Age development, with artistic evidence from the Near East dating to the mid-8th century BC.^5 The evidence in Greece is a lot more disputed.^6 It was probably there within 100-200 years of the Near East.
As for the origins of cavalry, they're still up for debate: was it introduced from the steppe, or a development in Assyria? The Robin Archer article that I've referenced gives a good overview of the competing theories, while making his own argument.
References
^1 Anthony, D.W. 2008. The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World.
^2 Archer, R. 2010. "Chariotry to Cavalry: Developments in the early first millennium", in New Perspectives on Ancient Warfare, p.69 n.33.
^3 Yadin, Y. 1963. The Art of Warfare in Biblical Lands in the Light of Archaeological Discovery, p.113; Beal, R.H. 1992. The Organisation of the Hittite Military, p.197; Spalinger, A.J. 2005. War in Ancient Egypt: The New Kingdom, p.11.
^4 Schilardi, D.U. 1999. "The Mycenaean Horseman(?) of Koukounaries", in MELETEMATA: Studies in Aegean archaeology presented to Malcolm H. Wiener as he enters his 65th year.
^5 Archer, R. 2010. "Chariotry to Cavalry: Developments in the early first millennium", in New Perspectives on Ancient Warfare, p.72.
^6 Worley, L.J. 1994. Hippeis: The Cavalry of Ancient Greece, p.1-6.