Were horses used in battle in 5th century AD Britain?

Were horses used in battle in 5th century AD Britain? Did the Romans, Celts or Germanic tribes use them in battle.
I look forward to your feedback.

I guess you have just watched King Arthur. Heavy cavalry depended upon the stirrup which was not present at the time.

Well its misleading to only talk about heavy (well equiped) cavalry.

Wikipedia says

“The domestication of horses, and their use to pull vehicles, had begun in Britain by 2500 BC; by the time of the Roman conquest of Britain, British tribes could assemble armies which included thousands of chariots.”
There was a change from chariot to riding the horse during those centuries, but for whatever use, the horse was available for military use.

Definitely Yes. With some possible fun stuff thrown in.

Tell that to all the ancient Near Eastern cultures that deployed stirrup-less cataphracts into battle. I’m sure that various Roman legionaries would be overjoyed to learn that those heavily armoured lancers thundering towards their flank are harmless due to lack of stirrups.

I think he’s talking about classical mounted men-at-arms style cavalry capable of a charge with couched lances. That didn’t come about until the invention of the stirrup, but prior to that, cavalry was quite often used in combat, but more as just mounted melee fighters instead of relying on the charge.

No, that is incorrect. It’s a long-standing meme that stirrups revolutionized cavalry warfare, but more modern research has indicated that said meme is overstated. It was an evolutionary innovation, not a revolutionary one. Other methods of grounding lances were used - high cantles with locking guards on the saddles, chains attached to the horse’s neck, grounding loops attached to the saddle. Undoubtedly less elegant solution to the problems of shock cavalry, but apparently functional ones.

By the later roman empire, roman military strategy did not just include cavalry, it was based on it. Rather than the older roman strategy of a heavily fortified border protected by legions (and neighbours who are cowed by a combination of the threat of the Roman military and roman trade and diplomacy), the later roman empire relied on fortified cities, and a “rapid reaction force” of heavy cavalry who could react to any invasion.

EDIT: It would be this type of roman warfare that the historical King Arthur (as a Romano-Brition fighting Anglo-Saxons) would have been familiar with.

They used more cavalry, true, but the late Empire military strategy was still infantry-centric, with the limitatenei being border troops who actually lived and farmed near where they were responsible for defending, and the mobile units, called comitatenses, which were more along the lines of classic legions. They still weren’t cavalry though.