Pros know that chunking related text in their documents makes it easier for readers to get their message. Writers have been using visual signals to create textual chunks since the ancient Greeks. The photo is a page from Ælfric’s Grammar, written in the second half of the 11th century, with large initials and both Latin and Anglo-Saxon script. I found it at a British Library site dealing with medieval and earlier manuscripts (Royal 15 B xxii, f. 2).
If you have an interest in paragraphs, you might also check out The History of the English Paragraph, for which Edwin Herbert Lewis earned the PhD in arts, literature and science from the University of Chicago in 1894. In 1911, he published a book titled, Business English, based on his experience teaching professional writing. I’ll say more about that later.
If your interests are more practical, here is a short tutorial on paragraph unity to help amateurs become pro writers.
- Amateurs think paragraphs are for babies (proswrite.com)