Before there were lawyers, there were philosophers. The Sophists, given a bad name by Plato, earned their bread by teaching people how to plead their cases in court. There being no professional lawyers in 5th century B.C. Athens, people had to represent themselves. Witness this tale (probably too good to be true) of the pre-Socratic Greek philosopher Protagoras:
It is said that [Protagoras] taught a young man on the terms that he should be paid his fee if the young man won his first law-suit, but not otherwise, and that the young man’s first law-suit was one brought by Protagoras for recovery of his fee.
Bertrand Russell, History of Western Philosophy, p. 75.