We all come to fencing through different paths and from different backgrounds. Some come from sport fencing backgrounds, some come from oriental martial arts. The result of this is that well all carry a certain amount of "baggage" with us. A certain amount where we read something and rather than going off exactly what is read we assume that we know what is being said based on our previous knowledge. This can lead us into issues.
We must remember to read the manuals that we are reading and read them with a similar perspective to the one which the writer wrote them. For example: in the case of an Elizabethan manual, it is important that late Italian knowledge is not read into it, or even later. This can often happen as a result of our history and our background and thus our assumptions. The classical fencer, with his foil and epee has four distinct parries which he remembers. The rapier combatant may use actions which may in part be similar to these but the actions may not be named or used in the same way. If the classical fencer reads these parries into a rapier manual then he can find himself horribly confused. We must ensure that we do not put anachronistic terms, theories and practices into a manual as it will cause problems with the interpretation.
This particular situation became most evident for me when teaching a class on di Grassi, and more to the point his single sword. This would seem to be relatively simple except my own assumptions got the better of me and began to cause issues. Giacomo di Grassi states:
For the defence whereof it is needefull that he ſtand at the lowe warde, and as the thruſt cometh, that he encounter it without, with the edge of the ſword, and increaſe a ſlope pace forward, with the hinder foote at the verie ſame time, by which pace he moueth out of the ſtraight line, and paſſeth on the right ſide of the enimie. And he muſt remember to beare alwaies the poynt of the ſword toward the enimie: So that the enimie in comming forwardes, ether runneth himſelfe on the ſword, which may eaſely happen, and ſo much the rather, when he commeth reſolutelie determined to ſtrike, or elſe if he come not ſo farre forwardes that he encountereth the ſword, yet he may be ſafelie ſtroken, with the encreaſe of a ſtreight pace:So my first reading, all assumptions engaged stated this: Parry the sword in third with a slope pace forward with the hind foot with the point toward the enemy, which he should run upon. If he does not move forward to strike if he does not. Easy, right? Wrong. Problem here is that with a parry of third, the point tends to be a little high, so there are hilt issues with the opponent's weapon coming in at the downward angle from the High Ward. This did not result in the nice clean execution that di Grassi describes at all. Working through it again, if the thrust from the High Ward is encountered with the blade of the sword in the fashion of a cut, a mandritta tondo, not a parry, the action works much more cleanly.
Be careful about when you are reading and interpreting the manuals and figure out what your assumptions are before they make a mess of things. Or at least be aware of them so that you can understand them and so that you can fix them. Manuals need to be evaluated from the point of view of the time in which they were written and using the terms from when they were written. Mistakes such as these were made by many fencing historians, it would be best for us not to repeat them and gain a greater understanding of these works.