I was interested to see just now that the Dead Sea Scroll fragments (e.g. this one) have clear spaces delineating the words.
Whereas we have, with the Hebrew Bible at least, an idea of where the line breaks were in poetry because of features like parallelism even though those breaks are not in the oldest manuscripts.
This got me wondering: when did explicit markers for textual organization at the level of the word, the sentence, the verse of poetry, paragraphs, and books come into existence? Whether it was punctuation, indentation, other whitespace...
Wikipedia has this to say about the history of the paragraph:
The oldest classical Greek and Latin writing had little or no space between words and could be written in boustrophedon (alternating directions). Over time, text direction (left to right) became standardized, and word dividers and terminal punctuation became common. The first way to divide sentences into groups was the original paragraphos, similar to an underscore at the beginning of the new group.
In ancient manuscripts, another means to divide sentences into paragraphs was a line break (newline) followed by an initial at the beginning of the next paragraph.
Is a more detailed summary available? How, where, and when did these things develop that seem so crucial to us?