Critics agree that William Blake was one of history's most deeply religious poets and paintersthough they cannot agree on what his religion was. In 1761, when he was only four, Blake startled his parents with the announcement that he had seen the Godhead at his window. In 1827, when he was near death, he flabbergasted his friends with a 100-page philosophical poem called Jerusalem, which he not only illustrated but engraved and printed himself. His contemporaries called it "perfectly mad."
Blake tried and failed to sell the only copy of the poem which he published in color. Last week the William Blake...