By the time John Milton began composing Paradise Lost in earnest in the early 1660s, he had been completely blind for roughly a decade, most historians tracing the total loss of his sight to 1652. He wrote nothing of the poem's more than ten thousand lines by hand. Instead he composed passages in his head, often at night or in the early morning, and dictated them the following day to whichever amanuensis was available: his nephews, paid assistants, and, by his own account and that of early biographers, his daughters Mary and Deborah, who are traditionally said to have taken dictation and read aloud to him from books in languages, Milton having taught them to sound out Latin, Greek and Hebrew phonetically, that he understood but they reportedly did not.
The practical difficulty of the method shaped the poem's own account of its making. In the invocation that opens Book Seven, Milton describes his Muse, Urania, visiting him nightly and dictating to him "slumbering," a line read for centuries as literal description as much as literary convention, given how the poem was actually produced. He sold the manuscript's copyright in 1667 for an initial payment of five pounds, with further payments contingent on print runs selling out, a modest sum even by the standards of the day for a work he had spent years composing entirely from memory and dictation, blind, in a country that had recently imprisoned him for his politics and briefly threatened his life at the Restoration.