Here’s someone who seriously needed a good agent: On April 27, 1667 impoverished writer John Milton sold the copyright for one of the most famous works in all of English literature, Paradise Lost, for £10 (though, to be fair, that was worth quite a bit more back then than it is now—about £15,000).
Milton lived in a turbulent time—he was born just at the start of the Stuart dynasty, saw the English Civil War break out, and was given a place in public office under the Commonwealth. His writings during that period defended popular government and even sanctioned the regicide of King Charles I, which did not put him in a good position when the Restoration came about in 1660. Milton lost his official position and had to go into hiding when Charles II returned. He was found and briefly imprisoned, but influential friends were able to get him released. He continued to write (or, rather, to dictate his writings, as he had gone completely blind in the 1650’s) but the work brought in little money, so the Paradise Lost copyright was sold to Samuel Simmons, a publisher, for £5 outright and a further £5 to be paid each time a print run of between 1,300 and 1,500 copies sold out. The first run sold out in 18 months. A second edition was being planned when Milton died in 1674.