Modern punctuation started with monks in the Middle Ages. They added a space between words. As part of telling the story of the printing press, and that writing is about communication, not rules, in 30 Philosophers, I set it up like this:
“Prior to 900 CE, [writing] had no case—it was all uppercase or lowercase. It had no punctuation at all: no spaces, no commas, no periods, no paragraphs. It was just letters strung together. For example, most historical documents written before 900 CE in the West, particularly Latin and Greek texts, employed scriptio continua, featuring all uppercase letters, with no spaces between words, no punctuation, no paragraphs.
Before around 900 CE, reading was an experience most of us would not recognize. Instead of having grammar guide the reader’s interpretation, they had to interpret the text. Sure, they grew up seeing patterns of words in a string of letters, but a reader of the time would read and interpret the text much more than we accept today. The aim was to convey meaning through the arrangement of words alone. Sometimes the process required rereading the text several times. In fact, there was the profession of a professional reader—someone who would stand in the town square and read announcements the way the authors wanted them read.”
My main point in the book is to empower personal writing style, not the grammar-freak rigid writer of an English class. Communication is king. And, breaking rules here and there, especially for effect, is more than perfectly fine.
After monks “invented” the space, adding grammar was slowly. By the time of the Magna Carta in 1215, punctuation was still mostly just spaces. However, by the time Copernicus published his famous book in the 16th century, we had modern writing with periods, commas, paragraphs, and even chapters.