Plate Mail!? (common misconceptions)

When developing The Lady of the Lake, I already had some background knowledge about equipment used in the Middle Ages, and I did some additional research on top of that. I felt compelled to make it at least slightly realistic when it made sense to do so.

Armor Terminology

• Plate mail -- No such thing. It should be "plate armor." (more info)
• Chainmail -- Technically "mail armor" (or "maille armor") is more accurate. (more info)

These mistakes might be passed down from Victorian times, but I blame Dungeons and Dragons. A ton of new RPG video games are still using these wrong terms.

Types of Weapons

The main issue with weapons in RPGs is an over-reliance on swords, and an under-reliance on other types of weapons. I think Dungeons and Dragons has some ways of making weapon variety useful, but it likely has some issues as well.

• Spears -- The most popular type of weapon throughout history. They are quick, offer reach, and can be used easily to parry. Even samurai mostly used spears, at least when they weren't using bows or guns. Most divine weapons used by gods are also spears, such as Zeus's Thunderbolt. Spears might not always be the best against heavy armor, but lances are basically spears that can be effective against heavy armor when on horseback. Some other spears were also popular because they are effective weapons for cavalry in general. (Samurai also often fought on horseback.)
• Swords -- I do not know a lot about the best use of swords. They were used a lot for close combat by the Ancient Romans. They are likely popular in part because they got expensive after they started getting forged using iron, so they were more often used by aristocrats or warriors with greater wealth.
• Axes -- I do not know a ton about the best use of axes, but my understanding is that they were popular. They are more effective against metal armor than swords.
• Hammers and maces -- When people started wearing heavy armor in the Middle Ages, hammers and maces became some of the most useful weapons. They tend to be good against heavy armor. Maces might be more effective against mail armor, and hammers might be more effective against plate armor. In any case, they are often better than spears or swords against metal armor. 

In Lady of the Lake, spears increase your agility and tend to be better at parries. Swords and spears are less effective against heavy armor. Maces and hammers are the most effective weapons against heavy armor. Since the game is based on the world of King Arthur, there are several Arthurian magic swords in the stories that are included in the game.

In Lady of the Lake, swords deal more damage than spears, and they are better for parries than most other weapons.

Types of Metal

One type of progression that often comes with buying equipment is to start off with bad equipment and having to upgrade each piece of equipment for something better repeatedly. One option is to consider the type of metal it is made out of.

• Bronze -- I don't think copper was used much. Bronze was popular before the iron age. Bronze weapons were cast rather than forged, so it makes sense for bronze weapons to be less effective and a lot cheaper. I don't know that the Middle Ages really used any bronze weapons anymore, but Ancient Greece did have a time when both bronze and iron weapons were used. It makes sense that there would be a transitional period like that.
• Iron -- Iron weapons were revolutionary and much more effective. It was worth its weight in gold more early on precisely because it was so useful. Iron weapons were forged, so that also made them more expensive.
• Steel -- Steel is more effective than mere iron. There's actually a huge variety of types of steel, and steel weapons were likely made at the same time as iron weapons first started being used.

In Lady of the Lake, some allies will start the game with bronze equipment, and the first equipment you can buy is made of iron. It doesn't take long before you can buy steel equipment.

Gold

Gold coins were unusual in the Middle Ages, and the main currency were silver coins. Gold coins were also worth a lot, and a single gold coin was sometimes enough to buy a horse or sword. The price of the coins fluctuated. At one point in history in England, a gold penny was worth eighty silver pennies. 

I decided that Lady of the Lake would have a more realistic monetary system. One gold piece is enough to buy an iron sword, and one gold piece is worth eighty silver pieces.

Copper coins were either incredibly rare during the Middle Ages or just were not used as currency back then. Some cities did use bronze coins.

Do you know of any similar misconceptions about the Middle Ages that are a bit silly and keep showing up in RPG video games?