Blake was born on 28 November 1757 at 28 Broad Street, Soho, London, the third son of James Blake (1723?–1784), a hosier, and his wife, Catherine, née
Wright (1723–1792), the widow of Thomas Armitage. Blake had four brothers, James (1753–1827), John (b
. 1755, d
. before 1760), Robert (1762?–1787), and John (1760–1800?), and one sister, Catherine (1764–1841). Records at St James's, Piccadilly, note the baptism of a Richard Blake in 1762, but this may be an error for Robert. Only James, who continued the family business, and Catherine played roles in Blake's adult life. The younger John was apprenticed to a baker but ran away to ‘enlist as a Soldier & died’ (Tatham in Bentley, Records
Blake was born into the class of London shopkeepers and artisans known for its hard work in pursuit of financial security and a tendency toward independent opinions in religion and politics. His mother had been a member of the Moravian church while married to Armitage. She left that sect shortly before marrying James Blake on 15 October 1752, but their children's early education may have been shaped by Moravian concepts and customs.
Little is known about the outer circumstances of Blake's childhood, but the special character of his inner life made itself apparent at an early age. When walking on Peckham Rye, aged ‘eight or ten perhaps’, he beheld ‘a tree filled with angels’ (Gilchrist, 1.7). On another occasion ‘his mother beat him for running in & saying that he saw the Prophet Ezekiel under a Tree in the Fields’ (Tatham in Bentley, Records
, 519). At about this same time, Blake showed an interest in the pictorial arts. While still a youth, he began sketching and attending auctions to acquire old and then unfashionable prints after artists such as Raphael, Michelangelo, and Dürer. The intertwining of extrasensory perception and artistic expression continued throughout Blake's life and is integral to his concepts of mind, art, and religion.
Blake's father disapproved of his son's reports about angels in trees, but he was supportive of William's ambitions in the arts, buying for his young connoisseur casts of antique sculpture for copying with pencil or pen. When ten years old Blake began to attend a drawing school directed by Henry Pars—apparently his first contact with formal education. His character and interests indicated that Blake would become an artist; his family's finances would dictate the first step toward such a career.