The Rhetorical Tradition includes an essay called "The Principles of Letter Writing." This anonymous essay was written during the height of Medieval Rhetoric and describes the principles and composition of letters; the name is an accurate representation of the content.
I actually found this topic of particular interest as I am learning the principles of business letter writing in another English class. I enjoyed the mental comparison between the letter styles described in "The Principles of Letter Writing" and contemporary expectations of a technical document.
One of the most fundamental, albeit obvious, observations is that letters in Medieval Europe were handwritten and therefore required less formatting standards. Modern letters must follow the format requirements subject to digitalization. Present-day letters must have consistent font, size, headings, spacing, and borders. In fact, most business letters even have decorative letterheads that must be consistent across an entire corporation. I wonder what Medieval rhetors might have thought of such finite, relatively obscurely defined, rules.
Another point of interest was the content differences between now and then. Now, we are encouraged to make our letters as quick, yet thorough as possible. In English 402, we are told to refrain from embedded prose and unnecessary details. Essentially, business letters should be highly condensed and concise. There is to be an introduction, short body, and conclusion only. If you write more than is required of the information, then others will not read it. Email has allowed communication to take place in an almost unmanageable degree. There is, quite simply, no way to read everything that is sent to a person in one day. Modern day rhetoric has made skimming acceptable, if not absolutely necessary. Therefore, in order to avoid missed information, people must condense their letters. My English 402 professor often says, "No one wants to read anything that you write." I do not know that it is that they do not want to read it, I just think it is because they logistically cannot read everything you write them. There is too much being sent in one day to capture every finite detail!
This modern level of constant communication is a far cry from handwritten letters of Medieval times. It took such effort to write a letter that the audience would dwell on every word. It was unlikely that an individual would receive more than one lengthy letter in a day; therefore, they had more time to appreciate it. I enjoyed the part in "The Principles of Letter Writing" that described content expectations. "There are, in fact, five parts of a letter: the Salutation, the Securing of Goodwill, the Narration, the Petition, and the Conclusion" ("Principles..." 497). I cannot imagine what it would be like if these expectations existed today; it would take hours just to get through one day's emails, let alone the hours it would take to send your own emails. Yikes, comes to mind. In any case, I really enjoy reading centuries-old letters as they are so beautifully and eloquently written. Letters of Medieval times are certainly less rushed, therefore seem more meaningful, than contemporary letters.