They were popular in the late Medieval period. Mace, warhammers, and battleaxes with thick heavy heads were very common sidearms for cavalry, not only in Europe (both Western and Eastern) but also in the Middle East and India. These soldiers also typically carried a sword as well. Both the mace/warhammer/axe and sword were usually sidearms, with a lance commonly being the main weapon (and later, pistols replacing lances). The couched lance, intended to transfer as much force from the motion of the horse as possible to the target, was quite possibly a much better anti-armour weapon than the mace etc. If the lance was broken or dropped, then either the mace or sword could be used, depending on the opponents.

These cavalry weapons were generally one-handed, and this meant that they were, on average, of similar weight to swords. They had two advantages against armour then compared to swords:

• More of the weight was at the far end, so they could hit quite hard compared to a sword of similar, or even greater, weight.

• They were less likely to be damaged when hitting armour.

However, they were not a panacea against armour. Armour designed to keep out lances, crossbow bolts, arrows etc. would still provide a lot of protection against these weapons.

There were two-handed warhammers on the battlefields, among the variety of polearms in use. Since they were typically about the same weight as many bladed polearms, which also had their weight concentrated at the head, both the blunt versions and sharp versions could be equally effective against armour (but blunt ones would be less likely to suffer damage, which would usually be to the edge). While heavily armoured infantry (men-at-arms including knights) were more likely to have two-handed warhammers such as pollaxes than other infantry who would be more likely to use halberds or bills (if not spears or pikes), we can note than many pollaxes had a cutting blade on one side, and many halberds and bills had spikes on the back of the blade. Both types of weapons could cut, and both could provide concentrated force against a small point.

Some past discussion about some of these points:

• https://www.reddit.com/r/AskHistorians/comments/bxfo1b/why_werent_blunt_weapons_more_prevalent_as_a/

• https://www.reddit.com/r/AskHistorians/comments/bt56r6/why_were_swords_more_popular_than_maces_in_the/ where in addition to my comments, u/Draugr_the_Greedy discusses the underlying martial arts.

It is because they are specialized weapons, and as many specialized weapons they are only used by the people who has uses for their specialization.

Maces have existed in some form since pre-medieval times, however with the introduction of plate armour they become less effective, not more. This is due to the rigidity of the armour which can tank blunt force a lot better.

Late mediecal times is also when you have reached the level of industry where swords are no longer expensive, and much like in ancient greece/rome most fighters can afford to have them.

The combination of cheaper swords and stronger armour gives a huge resurgence in the popularity of the sword as a convenient sidearm, something it was in Roman times but which it lost in the early middle ages. The versatility of the sword was favored highly. It is a defensible weapon which allows you to use it without a shield (which means that you can carry better polearms, the primsry function of smaller weapons is to be backups and this should not be forgotten), it is easy to carry around and it is also very useful to exploit unarmoured areas on your opponent.

Meanwhile hammers and maces are still not useless against armoured opponents, but you're restricted in your target areas so the huge advantage people imagine they hold over swords is not really that huge. They're on top of this short, more tip heavy (less versatile), much more reliant on powerful hits to deal damage even against someone not in armour, awful at defense and also less convenient to carry.

Which means there is one obvious place they shine - horseback use. Their tip-heaviness is a lot more useful there. Short reach is not much of an issue against footsoldiers and you're the perfect height to bonk peoples heads, which is the number one target for blunt force.

This is why these weapons see most use on horseback as backup weapons to lances (with swords also still carried to be drawn if needed). This is also why the concepts of 'horseman's hammers' or 'horseman's axes' exist.