Punctuation marks are symbols used to clarify meaning in writing. Early Greeks had little punctuation and wrote continuously with no spaces between words. Later, the Romans introduced dots between words and capitalizing first letters of paragraphs to make text easier to read. In the Middle Ages, punctuation broke down as few could read and write. Eventually words were separated and new sentences started with larger letters. Proper use of punctuation marks like periods, commas, colons helps clarify meaning and prevents reading problems. Improper punctuation can cause confusion, but these issues are still encountered today and require teaching readers proper punctuation rules.