William Blake was born on 28 November 1757 at at 28 Broad Street (now Broadwick St.) in Soho, London and was baptized on 11 December 1757 at St. James, Westminster, Middlesex, England, the son of James Blake and Catherine (Unknown).
His mother is reported to have been Catherine (Wright) the widow of Thomas Armitage 
William studied at the drawing academy of Henry Pars. He then served a five-year apprenticeship with the commercial engraver, James Basire, before entering the Royal Academy Schools as an engraver at the age of twenty-two.
William married after 18 Aug 1782 (banns) at St Mary, Battersea, Wandsworth, England to Catherine Butcher/Bucher, an impoverished grocer's daugher who could neither read nor write.
Another source reports her name as Catherine Sophia Butcher.
Blake taught Catherine to read and write and to use the printing press. Despite having no children, their marriage was successful. On his deathbed, Blake drew a picture of Catherine as his last work, stating "you have ever been an angel to me."
Death and Burial
Robert N. Essick, his biographer in the Oxford National Dictionary of National Biography states that William Blake died at Fountain Court at 3 Fountain Court on the 12th August 1827.He quotes a contemporary reference, written 3 days after his death, stating that he died
died on Sunday Night at 6 Oclock in a most glorious manner[...]
The burial register entry for the dissenter's burial.grounds at Bunhill fields records his burial National Archives on 17 August 1827. 
Originally, he was buried in an unmarked grave. On the century of his death a stone was placed over his grave. This commemorated both William and his wife Catherine Sophia whose grave was 70 metres away so was rather ambiguously worded. The stone reads
NEAR BY LIE THE REMAINS OF
THE POET PAINTER
AND OF HIS WIFE
The stone was moved in 1965 so is in fact now not over his original grave.
Two other christening records are of note. A christening record was for a William Blake, son of James Blake and Catherine (Unknown), on 21 November 1802 at St. Just in Roseland, Cornwall, England. Also a christening for a William Blake, son of James Blake, christened on 5 May 1758 at Crosscanoby, Cumberland, England.
↑ 1.01.1 Wikipedia contributors. Wikipedia Citing Raine, Kathleen. World of Art: William Blake. (Thames & Hudson, 1970) Retrieved 9 Mar 2018.
↑ 5.05.1 Barker, Elizabeth E. “William Blake (1757–1827).” In Heilbrunn Timeline of Art History. New York: The Metropolitan Museum of Art, 2000–. William Blake (1757–1827) (October 2004) Retrieved 9 Mar 2018.
↑England Marriages, 1538–1973. FamilySearch, William Blake and Catherine Butcher, 18 Aug 1782; citing St. Mary, Battersea, Surrey, England, reference p. 1782 No. 281, index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 1,041,673.
The National Archives of the UK; Kew, Surrey, England; General Register Office: Registers of Births, Marriages and Deaths surrendered to the Non-parochial Registers Commissions of 1837 and 1857; Class Number: RG 4 Piece 3997: Bunhill Fields Burial Ground, City Road, 1825-1828 viewed on ancestry.co.uk
↑ According to Charles Reed, William Blake, "...celebrated Engraver and Poet... He was a person of eccentric character, and his etchings were remarkable for their peculiar and original manner. He died August 12, 1828
Reed, Charles. History of the Bunhill Fields Burial Ground. (London: C. Skipper and East, 1893) HathiTrust.org Page 34. This appears to be an error since The 12th August 1827 was a Sunday which conforms with the information in the ODNB, and the burial record for 1827
↑England Births and Christenings, 1538-1975. FamilySearch, William Blake in entry for James Blake, 21 Nov 1802; citing ST JUST IN ROSELAND, CORNWALL, ENGLAND, index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 246,801.
↑England Births and Christenings, 1538-1975 FamilySearch, William Blake, 05 May 1758; citing Crosscanoby, Cumberland, England, index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 90,600.