A question I've found myself asking a lot is, what is the durability of maille armor? Especially the knightly sort one would find on a well-to-do nobleman such as William Marshal during the XII Century? Reading on the armor info here there are accounts of it standing up to lance strikes, but there are also examples of it being pierced by lances too. Is this due to variation of make between hauberks, say, poorly welded armor versus fantastically smithed stuff or even mysterious "tournament maille"? Have any detailed tests been done on accurately determining the strength of various types of knightly maille armor? While I certainly get the impression is far superior to any meme Hollywood idiocy by the simple nature of medieval tournaments from the time of William Marshal, which were less our idea of an organized joust and more a mob of hormone-fueled bloodlusting warriors mercilessly hacking into each other with real blades and only not going so far as to finishing each other off with daggers, but still using lances- yet I've also heard maille can be penetrated by something so simple as a falchion.

The two main factors are the quality of the materials and build of the mail and the padding underneath, which some would argue was the most important aspect.

There is, to my knowledge, nearly nothing written about mail armour and its quality in the 12th century. The main evidence we havr is indirect, through specific mentions of times when mail armour failed-or held strong- in a given situation. Also, we have so little surviving mail from this time that trying to make generalizations is essentially impossible. Making things more difficult is that some of the mail from around this time is so severely corroded that we must make guesses about its original state. So primary sources, both documentary and archaeological, are thin on the ground.

One factor that we know could make a difference is the internal diameter of a mail ring. This differed over time, and might have made a significant difference. Padding, as Mark mentioned, matters- mail is substantially more protective combined with textile armour. Also, as you will know if you've read Mail: Unchained, there is also the enigmatic matter of "double" mail.

As far as I know there are very few first rate people recreating mail armour these days. Trying to test mail armour that you've purchased online will probably not accurately similate medieval mail. So a lot of research remains to be done.

Alan Williams shows the medium-carbon, hardened steels used in Renaissance mail could be 7x harder than the wrought iron used in Roman and Dark Age mail. During the "Age of Mail", steel mail cost 2-3x more than iron mail. Another factor is the ring diameter, where smaller internal diameters make mail harder to penetrate, but more laborious to produce. A simple reduction from 9mm to 6mm internal diameter requires almost 300% as many rings per square area.

We know that they distinguished tournament mail from mail for war, but the distinction is obscure. It could be that such mail was lighter, as some tournaments used rebated or mock swords. Or it could have been heavier to reduce risks, since tournaments were only a game.

We do know that mail sometimes appears in inventories as rusty, missing rivets, or in need of repair. So like any armor, it needed to be maintained and cleaned.

There are some specific references to mail being damaged or penetrated in the late-12th and early-13th century chansons, but opinions vary in how much trust should be placed in these heroic tales. Are they more or less reliable than some Hollywood fantasy? Humans have been known to perform extraordinary feats under the influence of adrenalin.

The best info we have on mail from this period is that some wore it and some didn't. Some that wore it were killed, some weren't. To say much more would require a heck of a lot of research and testing at quite a high level of accuracy. As we have no mail that can be positively identified as 'knightly', or any other class of warrior, you'd be essentially trying to recreate something that doesn't exist, making it a bit tough. We have best guess stuff but that's all.

16th-century English military writers didn't seem to consider mail proof against the pike or lance. Sir John Smythe wanted all pikers in the front ranks to have plate arm defenses while he allowed for mail sleeves for halberdiers. Humphrey Barwick dismissed all of Smythe's recommended lighter, easier armors, including jacks of mail. See this thread. Of course, it's unclear what bearing 16th-century sources have on earlier periods. Both mail and the weapons used against it vary by period and quality.

It's one thing to stop the sharp point of a lance or pike from penetrating mail, quite another to keep the wearer's rib cage from getting smashed in. Ribs still get broken in modern longsword tournaments from time to time right through thickly padded jackets that are constructed in such a way that they have a double layer on the chest. Basically what it comes down to is the padding can be deformed past the breaking point of your ribs, or another way to think about it is you can fold the padding but you can't fold your ribs without breaking them. Rigid or even semi-rigid plates are much more efficient at preventing that kind of injury. If mail clad knights were surviving lance strikes to the torso there was something under their mail besides just a gambeson.

In the Couronnement de Louis (Li coronemenz Looïs) from 1137, Guillaume l'Orange faces off in a one-on-one combat with the Saracen Corsolt. In L.XXVI, lines 1045-6, we get this example of the strength of Count Guillaume's blows:

Li cops fu granz si vint de grant randon;
que iii.c. mailles en abat sablor.

The blow was huge and it came with much speed;
it cast three hundred rings on the ground at his feet.


Chrétien de Troyes' Yvain from the 1170s, (Trans. W.W. Comfort) has these descriptions:

Quote:

Each one carried a stiff, stout lance, with which they dealt such mighty blows that they pierced the shields about their necks, and cut the meshes of their hauberks;..... They are careful not to waste their blows, but lay them on as best they may; they strike and bend their helmets, and they send the meshes of their hauberks flying so, that they draw not a little blood, for the hauberks are so hot with their body's heat that they hardly serve as more protection than a coat. ..... There is not a mesh that does not spread, and the sword cuts the flesh of his neck beneath the shining mail, so that it causes the blood to start...... For they strike each other violently, not with the fiat of the swords, but with the edge, and they deal such blows with the pommels upon the nose- guards and upon the neck, forehead and cheeks, that they are all marked black and blue where the blood collects beneath the skin. And their hauberks are so torn, and their shields so broken in pieces, that neither one escaped without wounds.

Which goes to show that the purpose of mail was not to make you invulnerable to wounds, but to prevent mortal wounds.

In King Olaf Trygvason's Saga in the Heimskringla, it was written that King Hakon was hit with so many spears and arrows that his mail was completely destroyed. He threw the remains off onto the deck of his ship and continued to fight without it. He even kept a piece as a souvineer to show his friends how much damage it took:

The ring-linked coat of strongest mail could not withstand the iron hail,
Though wrought with care and elbow bent, by Norn, on its strength intent.
The fire of battle raged around, Odin’s steel shirt flew all unbound!
The earl his mail from him flung, its steel rings on the wet deck rung;
Part of it fell into the sea, a part was kept, a proof to be
How sharp and thick the arrow-flight among the sea-steeds in this fight.

Despite being hit with enough weapons to destroy his armour he survived to boast about his prowess.

The top gambeson usually seems to be sleeveless, so it functions pretty much as a breastplate, I don't think it affects movements much.

It is interesting to note the language used in the chansons describing hauberks being damaged: "ripped", "torn", etc. rather than "cut".

A search within this text for hauberc brings several examples.
https://www.google.com/search?tbo=p&tbm=bks&q=isbn:0859917819