The Harleian Manuscript 3542 (ff. 82-85) is, essentially, a short set of instructions on the use of the two hand sword (or longsword) written down some time in the early 1400's in medieval England. It is a rare example of medieval English martial arts in lesson format. It is located within the greater corpus of the Harleian Manuscript 3542. The portions of the original manuscript which are continguous with the fencing instructions are solely concerned with alchemical theory and recipes, providing an important contextual clue to modern researchers as to the relative importance of fencing compared to other disciplines and the mindset of those who might have studied said art.
The Harleian Manuscript is a copy of two separate (but certainly related) works, comprised of the late 14th century "Man that Would" rhyme and then the early 15th century lessons that--in this scribe's copy--precede the rhyme. The original manuscripts from which these two works were copied have been never been found. Nothing is known for certain of their provenance or their intended use, although educated speculation and careful examination suggests that they may have been the notes of a student, or the notes of a teacher, intended as sort of a lesson plan. Certain word choice--especially in the rhyme--provides tantalizing suggestions that this particular form of swordsmanship may have seen use in a "wager of battle"--that is to say, trial by combat.
The first eight plays described in the manuscript seem intended as solo drills, either against a pell, or at the open air. This type of exercise is not unknown in eastern martial arts (such as iaido), and practical recreation shows that many of these plays are good for developing muscle memory and stamina. Their explicitly stated purpose within the text is to make a fencer's "hands and feet accord." That is to say, to develop good coordination in the basic movements of the style.
The next eleven plays probably include a partner in their execution. The section begins with "the play of the two hand sword between two bucklers" and the enumeration of the plays following resets to the beginning. This would seem to indicate a separate section of study from the solo plays before. It is possible that the next section "the encounter of the two-hand sword" is an incomplete follow-up to the "two bucklers" section, and represents a "patient agent" role for the prior exercises.
It is worth noting that the "Man that Would" rhyme explicitly assumes that your opponent will be wearing armor. Thus, the style of swordsmanship therein described represents a rare look at the art of armored combat without use of "half-sword" techniques as are often depicted in Continental texts. Although it is certain that medieval English swordsmen were familiar with such techniques, it is interesting to note that attacks described in the Harleian Manuscript assume effectiveness of "strokes" against armor, giving us a valuable clue as to the type of armor worn and the areas it covered. Although it is practiced in the BFSA as an unarmored art (due to restrictions in practicality of equipping several students at a time with properly fitted and weighted late 14th century harness), it is important to remember that these techniques are meant to be executed while wearing--and effective against--armor.
The following transcriptions and translations by Benjamin Roberts are from photocopies of the original manuscript, courtesy of the British Library.