In my four years in the SCA, I've seen a fair people gotten hit in the cup with rattan sticks, watched videos of people collapsing in pure agony after getting hit in the cup with a rubber war hammer, gotten kicked in the groin as a kid and felt, watched movies and TV series of people of people bleeding like slaughtered pigs after getting a their nuts ripped off, slide in between the legs, et.I've alsolook at various armour style across different periods on here and just musing. One of things that always strucks is the seeming lack of any sort of rigid protection in Western European armor for the groin until around the 1500s. Anyone can explain this? Why rigid groin protection is so seeming rare in armor throughout time?

Because shields and non-rigid armour work well enough?

As well as being protective, the armour needs to be not-too-inconvenient:
- If you have close-fitting rigid groin armour, can you walk all day in it?
- If you have stand-off rigid groin armour (e.g., a tonlet), can you walk all day in it, and sit down in it?
- Can you ride a horse with it?

Things like lamellar/brigandine skirts, plate tassets, mail skirts, etc work. Maybe not as well as the best possible protection, but not too bad. Well enough so that until civilian fashion dictates that armour should include a codpiece, why suffer the problems?

(Only remember one hard groin hit from SCA fighting. Two-handed axe. Didn't hurt, but it did take links off my mail skirt.)

In the Adrian Empire we're all "supposed" to wear cups, but in reality...

In short, it isn't an issue. the groin is one of the hardest places to hit, let alone successfully hit with a weapon. between the faulds and tassets of my breastplate and the cuisses my boys are quite protected. If there is an inherent problem in the SCA with groin strikes, it makes me wonder more why you guys keep aiming for the dick than why period armor "doesn't" protect the groin.

The hauberk and jack tended to cover the groin, didn't they? For rigid defenses, I'd look at how groin protection changed in relation to the development of more thrust-oriented weapons and techniques. The plate fauld covers down the hip joints, which would tend to protect the genitals from slashing attacks from above.

Don't forget that the default mean of transport for an armoured man is a horse!

Riding in rigid groin protection will either damage you or the saddle (saddles have always been pricey pieces of equipment to boot) So I have a distinct feeling that is why we see some steel cod pieces for exclusive suits of foot torney armour, but for field armour not so much.

I recall seeing a tonlet armour that was designed for riding. Big cutout at the front (and, I assume, at the back) of the skirt. The cutout also meant it didn't protect the groin.

When it comes to equestrian armours, it's common to have no protection for the buttocks, for the inside thighs, for the back of the thighs. What's an exposed groin (or a mail-protected groin) compared to those gaps?

Yes, those areas aren't exposed when riding. But one is not always on one's horse. Men-at-arms might dismount to fight, or, when fighting mounted, their horses can be killed.

If you're worried about opponents lifting up flexible defences and stabbing underneath, either (a) don't let them do it, or (b) go for Henry VIII spacesuit groin protection. A cup is not enough against that kind of thing. You need to protect the whole groin area, not just the genitals. A cup doesn't protect enough. (a) is the practical solution for most people.

Where stabbing under groin armour will be a real problem is when wrestling. It will be a problem with flexible armour, with tonlets, and with cups. Which is an excellent reason to have "spacesuit" armour, if you can afford it, and only need to put it on for the tournament. Otherwise, some risk is acceptable on the battlefield.