Just 350 years ago, in April 1667, John Milton sold all rights to Paradise Lost to the printer Samuel Simmons — for £5, with another £5 due once Simmons had the first run of 1,300 copies off his hands. That sounds like a bargain for the 12-book epic poem of Satan’s war with Heaven, Eve’s ‘fatal trespass’ and the expulsion from Eden that soon became a monumental pillar of the literary canon.