There seems to be too much argument here :-) We indeed need a common vocabulary. Looking at all the evidences both for and against edge-to-edge blocks (and by "block" I mean action that stops the incoming blow) I see a lot of very different quotes from manuals written in different centuries and addressing different weapons.
Some of these quotes don't describe blocks at all, for example "Hold the sword with your arms extended long in front of you, or sink into the guard of the Fool; if your opponent cuts at you with long cuts, then slice them off from you with the long edge to both sides, until you see your opportunity to come to another work more suitable for you" (posted by William Carew, longsword): this technique is not a block, but a deflection.
There are quotes from rapier manuals (and specifically thrusting rapier manuals such as Capo Ferro). Well, rapier is not a cutting weapon. Some rapiers could cut better than others, but in general cutting with a slender rapier is risky. And rapiers often had cross sections that allow blocking edge-to-edge. There are different weapons, we should understand that what works with one weapon may not work very well with another.
There are quotes from dussack manuals. Again, dussack is a short but broad weapon, without a crossguard and relatively cheap. This weapon can withstand deep nicks far better than for example a longsword. Also one-handed dussack cuts are much weaker than two-handed longsword cuts. By the way, were there any sharp dussacks?
And there are even some pictures without proper quotes. Vincent Le Chevalier, picture on p. 68 of the manual looks as if both opponents are cutting at each other's swords in mid-air, non of the fighters seems to be aiming at his opponent. Please quote description of this technique, or next time I will post a picture from Mac. Bible as a proof that it is possible to cut a
maille-clad opponent in two. No offence, I just like original sources and am very suspicious of interpretations.
What I want to say is
1) I don't think anyone here says that edge was not used for parrying. What people including me say that edge should not be used for parries that inflict heavy damage to the defender's weapon. Such parries are hard edge-to-edge blocks. "Hanging" executed with an edge that I described earlier would leave a cutting edge totally blunt. Not an irreparable damage but having an edge of a cutting weapon totally blunt is not a good idea, is it? So it is also not a thing to learn.
2) Some weapons are better suited for edge-to-edge blocks than others. Thrusting rapier can be used for blocking cuts from another thrusting rapier because it is thick, does not need (and often does not have) an edge suitable for cutting and cuts with such weapon are rare and are very prone to breaking the attacking blade. And of course edge can be used for deflecting thrusts.
3) Weapons of same type can have very different design. I am pretty sure that forte of this weapon
[ Linked Image ] can be safely used for blocking edge-to-edge.
4) Overall economical, technological and cultural situation can have a great effect on fencing style. Military saber fencing manuals that show almost exclusively edge-to-edge blocks (at least I have such impression) are a good example. Most proofs for edge-to-edge blocks come from late 16th century sources. There are probably many reasons. One of these reasons may be dominance of the rapier that was well-suited for edge-to-edge blocks. But maybe weapons became cheaper and overall quality of steel also improved? I don't know.
5) There even seems to be dedicated sport fencing. Were there any sharp dussacks? I have an impression that dussack was a purely training weapon.
We should be more precise in our statements and not blindly apply what is said about one time period, region and weapon to other regions, weapons and time periods.