Milton was 43 when he went completely blind. The cause of his blindness is debated, but it is most likely that it was bilateral retinal detachment of glaucoma. John Milton (1608-1674) was an English poet, polemicist and a civil servant for Commonwealth of England under Oliver Cromwell. Milton is best-known for his epic poem "Paradise lost" from 1667, written in a blank verse. While writing his magnum opus, from 1658 to 1664, Milton was already blind and impoverished. As a blind poet, Milton dictated his verse to a series of aides.