Wrestling, in any era, culture and geographic era, is an archaic aspect of man, as a game, during the growth, and also as a ritual and sport activity. At the same time it is a fundamental and essential part in a warrior’s martial preparation.
German fencing treatises from the XV and XVI century clearly show how much attention was paid to wrestling, at least in Central Europe: just bear in mind the essays by Ott Jud, or by Fabian von Auerswald, or the Das Buch von Füßringen, or the Kunstlicher stuck Kämpffens Ringens und Werffens.
Only a little part of the copious Italian treatises of that period is dedicated to wrestling. Actually only three Masters wrote about it in significant way: Fiore dei Liberi, Filippo Vadi and Achille Marozzo.
As you may know, the “De Arte Gladiatoria Dimicandi” is deeply based on “Flos Duellatorum” (Pisani Dossi codex), so finding corresponding wrestling techniques between the two essays can’t be surprising. By the other hand the affinities between Marozzo’s wrestling techniques, from Opera Nova essay, and the ones described by the two medieval masters, are very intriguing: although there are no evidences of fencing traditions linking medieval masters to the renaissance ones, are we allowed speaking about an Italian wrestling tradition?
The answer is likely negative, since there are no solid evidences proving it.
Nevertheless, the comparison shows interesting similarities. There are few wrestling action in all three essay, showing a concise and efficient form of fighting; an approach aimed to pure efficiency: wrestling is required to finish the fight in short time.
Fiore dei Liberi sees wrestling as a lethal action, or at least decisive, extremely dangerous even if there are no real harmful intention (sono prese e zoghi che non se pò çugar de cortesia, anche sono çoghi pericolusi da çugar – these are grabs and games which are impossible to play nice, also these are dangerous games to play) Medieval and Renaissance wrestling purpose is to break opponent’s balance and knock him down, as well as dislocate his shoulder and break his elbow. Or worse (…li dedi polisi io metto in l’ochi soi s’il volto suo i’ truovo discoperto – I will put my thumbs into his eyes, if I find his face unprotected).
Doubtless one of the reason is that in all the manuals most of bare hands techniques are against someone armed with a dagger: it is a priority to have the adversary or his armed arm neutralized. It is possible to start analyzing the affinities amongst action like these.
The following pages show some comparisons between similar techniques. For completeness sake, I show also some techniques which are consequent to others or conclusive, even if uncommon amongst the three Masters.
Collar grab
In order to deliver a dagger stab without allowing the adversary to escape, usually an aggressor grabs him by his collar.
This action, quite frequent as treatises report, can be countered in many ways by breaking the elbow or twisting the shoulder of the arm that prevents us from fleeing or violently knocking the aggressor to the ground, before he can hit.
First action, described by both Fiore dei Liberi and Achille Marozzo, is to hit with the forearm the aggressor’s elbow, from outside to inside, in order to dislocate it or break it. 
The second action, instead, requires to hit from above with both wrists on aggressor’s wrist, in order to force him to leave the grab. Immediately after that both hands must be projected forward to block any potential incoming stab.
Fiore dei Liberi gives some alternatives to this action, like, for instance, hitting from above with right elbow on aggressor’s left arm, or violently rising down-up both wrists.
Both these solutions are not reported by Opera Nova, much more concise than Flos Duellatorum. 
It is obvious that, as soon as the grab is broken, we have to immediately knock down the aggressor.
Dislocations and fractures
The three authors have a number of defenses against dagger, which, if not identical in their number, are essentially identical in their execution, since they are all based on joint twists and dislocation.
Fiore dei Liberi defines two shoulder joint twists: the chiave sottana (lower key) and chiave mezzana (middle key). This naming convention suggest the existence of a third one, chiave soprana (upper key).
Vadi, obviously, reports the same actions in an identical way; same thing does Marozzo, although without proposing the same variants.
The chiave sottana, can be executed by acting at the same time but in different directions on wrist and elbow, pushes the adversary to bow forward to avoid the shoulder twist.
From this position it is possible to immobilize the adversary or dislocate and break the arm. 
The chiave mezzana acts using opposing forces in comparison to the chiave sottana, pushing the wrist and pulling the elbow of the opponent, trying to dislocate his shoulder.
It is possible to execute the chiave mezzana also using one arm only. However the opponent could use a chiave sottana to contrast the action. 
The action we could define chiave soprana, is a solicitation of the articulation which aims to violently dislocate the shoulder joint and, if possible, to knock the opponent down.
You must block the opponent’s forearm, or grab his wrist with both hands, and, then pushing downwards and towards the opponent’s shoulders, possibly using your own humerus as lever fulcrum. 
Different actions, with same result, can be done by putting the opponent’s arm on your shoulder: once the opponent’s forearm is grabbed with both hands, turn on yourself so that he is behind you.
Then put your arm or his humerus on your shoulder. Now it is sufficient to continue pulling down, (better if you keep rotating), to break the elbow or dislocate his shoulder. 
Fiore dei Liberi, imitated by Filippo Vadi, suggests a counter, in case you are able to turn the arm and bend the elbow, avoiding the lever. 
Knocking down
The best way to neutralize your opponent after a joint dislocation or a balance break, is to knock him down, possibly making him hit the ground with his head, as suggested many times by Fiore dei Liberi.
The easiest way to knock someone down consists in lifting the opponent, and throwing him to the ground. Examples of “bear grabs”, in front or behind, can be found from ancient Egypt (Oxyrhynchus Papyrus 466).
You can also lift the opponent up loading him on your shoulder(s).
This is the solution Achille Marozzo suggests, which is identical to Fiore’s, and very similar to Vadi’s.
In case the opponent is heavier than you, instead of loading him it is preferable to unbalance him backwards, putting a leg behind his supporting leg.
You can grab the opponent’s throat, or seize firmly his neck with your arm. Then you have to turn, so that he will stumble on your leg, which you moved behind his own.
In another case, you have to rotate while pushing on your opponent’s breast or neck with your forearm, or even putting an hand under his jaw, trying to bring his head backwards, so that, falling, he will crash it on the ground, as frequently suggested from Fiore dei Liberi. 
If it is not possible to get behind his legs, you have to grab his forward leg and push him backwards with the other hand, while raising his leg, until he falls back. 
Bottom line
Concluding this brief examination, although it is probably not licit to speak of “Italian wrestling tradition”, we must acknowledge the strong analogies between Achille Marozzo’s techniques and the ones of his medieval predecessors, both in typology and execution.
On one hand, these techniques are based on very simple principles, without more or less complex variations (at least in the Opera Nova ones), so that it may be more correct to attribute these similarities to a mere matter of anatomy and immediate effectiveness.
It is indeed true we can find a lot of these techniques, without substantial differences, not only in the German kampfringen of the same historical period, but even in the Classical era pankration, or in the more recent Japanese ju jitsu. And that comes as no surprise, because the weapon “human body” is common for all the human race, both in morphology and utilization.
This demonstrates, according to me, that successful solutions in unarmed combat, especially talking about wrestling, must be based on the same principles.
On the other hand, as also the akin article by Roger Norling, about the comparison of the unarmed techniques against a dagger armed opponent of Meyer with those of Marozzo, shows, do exist some significant parallelisms that deserve more careful examinations.
