From Amadis of Gaul:
When Garci Rodríguez de Montalvo wrote his version of Amadis of Gaul, he probably wasn’t thinking of payment. In medieval times, writing was either a gentlemanly avocation or a vocation sponsored by a gentlemanly patron. Books were hand-copied, so literature couldn’t be commercialized. Montalvo was a gentleman whose occupation was managing the city of Medina del Campo near Valladolid.
But only a century later, the printing press had come into being and had turned books into an affordable mass commodity. Miguel de Cervantes wrote Don Quixote de la Mancha, a parody of books like Amadis of Gaul, for money. Writing had become a profession, and professionals got paid.
What did Cervantes earn for Quixote? We don’t know, but we have enough clues to try to guess. Cervantes was poor before it was published and poor after it was published, so it wasn’t a huge amount of money. Everyone agrees on that.
. . . .
Don Quixote de la Mancha was published in two parts, the first in 1605 and the second in 1615. Cervantes didn’t plan on a second part, but after another author wrote a continuation, he decided to write his own.
In 1604, Cervantes was 50 years old and living in Valladolid. He had written a short story about Don Quixote, and he presented the idea of a novelization to publisher Francisco de Robles, who agreed and urged Cervantes to get it ready fast. Then the book was hastily edited (which explains the many errors in the text), printed on cheap paper with worn type, and rushed to the market.
Probably no one considered it a universal masterpiece at first, but the first edition of 1,000 copies sold well — in fact, it was immediately pirated in Lisbon. Cervantes had already won notice as a playwright, and this book cemented his reputation as a major writer.
He had received a 10-year royal privilege to print Don Quixote, which he sold to Robles for an unknown amount; the paperwork was lost. But he had sold an earlier novel, La Galatea, to Robles’ grandfather for 1,336 reales, of which he eventually only received 1,086.
Nieves Concostrina, a journalist with Radio Nacional de España, reported in the series Acércate al Quijote that he received no more than 100 ducados (which equals 1,100 reales or 37,500 maravedíes) for the copyright, which she estimates is worth only about €200 today.
Daniel Eisenberg, the former editor of Cervantes, the scholarly journal of the Cervantes Society of America, wrote that he probably received 1,500 reales (51,000 maravedíes), which he says would have been worth 500,000 pesetas in 1992, or €5,503.72 today. That’s better, but no J.K. Rowling.
Link to the rest at Amadis of Gaul and thanks to MKS for the tip.