William's name is spelled in a variety of ways: Baccus, Bachus, Backhaus, Baccheus, Backhouse, and Backus.
Everett Bingham, in "William Backus of Sheffield, Yorkshire, and Norwich, Connecticut" (NEHGR 1988) says that records of the Cutlers Company in Sheffield show that "William Backhouse [sic] was listed as an apprentice to William Nutt of Grimesthorpe, near Sheffield, Yorkshire, had been given his freedom in 1627, and in 1631 was admitted to membership in the Sheffield Cutlers Company." Bingham says that he signed by mark, using two precise letters, a W directly over a B -- the same mark the New England immigrant used in signing his will in 1661.
Thomas Bingham, husband of Anna Fenton, whom William married as his second wife, was a member of the Sheffield Cutlers Company at this same time. The baptisms of five children of William Backhouse, and the burial of his first wife and two of their children, are found in the Sheffield parish registers. (Bingham cites Yorkshire Parish Register Society, 1917.) Based upon these findings, Bingham estimates that William was probably born about 1606 near Sheffield, and probably married (1) Elizabeth (___) about 1627.
Older accounts assumed Sarah Charles to have been his first wife; it has been proven that she was the first wife of his son, William Backus Jr. By 1659 William had married (2) a widow, Mrs. Anne Bingham. Early writers called her Anne (Stenton) Bingham or Anne (Stetson) Bingham, but the record of her marriage to Thomas Bingham shows her to be Ann (Fenton) Bingham.
William Backus of Saybrook and Norwich, Connecticut is said to have been in New England as early as 1637, but proof is lacking. "Hale, House and Related Families" states that "he was early of Saybrook, Conn., but appears little of record." In view of his wife's burial in Sheffield 9 February 1643, it seems more likely that he immigrated after that date.
In a town meeting of January 1648, William Backus was one of 12 men assigned land across on the east side of the Connecticut River, in the area which later became known as Lyme. The soil around Saybrook was thin and unproductive, and some of the settlers wanted to move to better ground. Mohegans under Chief Uncas occupied the Connecticut River valley; the Narragansetts were to the east. When the home stockade of the Mohegan was surround and placed under seige by the Narragansetts, Chief Uncas asked the English colonists for help. A relief party set out from Saybrook under Lieut. Leffingwell, breaking the siege. In return, the Mohegans later granted the English a generous tract of land "nine miles square" around the head of the Thames River. The settlement was first occupied in the fall of 1659, and more fully settled in the spring of 1660, and became the town of Norwich.
William moved to Norwich with his second wife and family in 1660, taking out proprietary rights for his son Stephen and his stepson Thomas Bingham. The elder son, William Jr. had a share in his own right. The sons appear on the records of the original proprietors of Norwich, but William Sr. does not.
On 28 August 1661 there is an official record of property transferred to son Stephen. Reno Backus presumed this meant that William had died before this date, but it could have meant Stephen had just come of age. Torrey gives "1661?" as a possible death date for William, probably based upon this fact. Most accounts, however, give William's death date as 1664.
A William Backus was made freeman, in a group of Norwich men, October 1663 (CT Col. Rec. 1:412) -- this would be consistent with the 1664 death date, but the freeman of that date might have been his son William instead.
His will is dated 12 June 1661 and is signed with his initials. It was probated 21 June 1665 in the New London court. He specified that his wife should live with his son Stephen, or he to provide for her; his son William to have his smith and cutler tools, ivory and bellows; to "all the rest of my children," John Renalds and his wife, Benjamin Crane and his wife, John Bayly and his wife, with "all there children which are now liveing"; also Thomas Bingham ("and his wife" crossed out); friends Thomas Leffingwell and John Berchard to be overseers. Witnesses: Thomas Tracy, John Post.
Inventory taken 7 June 1664 and recorded in Hartford amounted to L102. It included house and homelot, a parcell of land in the Little Plaine, a parcell of land in the Great Plaine, a parcell of meadow at Yantick, and another parcell at boggy meadow. In addition there were the usual farm animals and implements, household stuff, and "a gun & a sword." Inventory was usually taken shortly after death, so this is probably our best approximation of the date of William Backus' death.
Some sources add a son Samuel "died young"; this appears to be a confusion with a son of William Backus Jr.

• Married: BEF 1635 ⁸

1. Sarah BACKUS c: 31 AUG 1628 in Sheffield, Yorkshire, England
2. (child) BACKUS b: ABT 7 JAN 1630/1631
3. Mary BACKUS c: 6 MAY 1632 in Sheffield, Yorkshire, England
4. William BACKUS c: 30 NOV 1634 in Sheffield, Yorkshire, England
5. Lydia BACKUS c: 31 DEC 1637 in Sheffield, Yorkshire, England
6. (child) BACKUS b: ABT 28 DEC 1640/1641
7. Stephen BACKUS c: 3 JAN 1640/1641 in Sheffield, Yorkshire, England

• Married: ABT 1659/1660 ⁹

1. Title: William Backus of Sheffield, Yorkshire, and Norwich, Connecticut
   Author: Everett F. Bingham
   Abbrev: Bingham
   Publication: The New England Historical and Genealogical Register, 1988, 142:253-254
   Abbrev: Backus of Sheffield
2. Title: The Backus Families of Early New England
   Author: Reno Warburton Backus
   Abbrev: Backus
   Publication: Privately published, 1966
   Abbrev: Backus Families
   Page: pp. 4-9
3. Title: Genealogical Dictionary of the First Settlers of New England
   Author: James Savage
   Abbrev: James Savage
   Publication: Originally published 1860-1862. Reprint published Baltimore MD: Genealogical Publishing Co., 1994
   Abbrev: Genealogical Dictionary
   Page: 1:89
4. Title: Hale, House & Related Families
   Author: Donald Lines Jacobus & Edgar Francis Waterman
   Abbrev: Jacobus & Waterman
   Publication: Hartford, CT: The Connecticut Historical Society, 1952
   Abbrev: Hale, House
   Page: pp. 452-456
5. Title: History of Ancient Windham, CT. Genealogy. Containing a genealogical record of all the early families of ancient Windham, embracing the present towns of Windham, Mansfield, Hampton, Chaplin and Scotland
   Author: William L. Weaver
   Abbrev: Weaver
   Publication: Willimantic CT: Weaver & Curtiss, 1864
   Abbrev: Ancient Windham
   Page: pp. 58-59
6. Title: The Granberry Family and Allied Families
   Author: Edgar Francis Waterman & Donald Lines Jacobus
   Abbrev: Waterman & Jacobus
   Publication: New Haven: Tuttle, Morehouse & Taylor, 1945
   Abbrev: Granberry Family
   Page: pp. 163-164
7. Title: New England Families Genealogical and Memorial
   Author: William Richard Cutter
   Abbrev: Cutter
   Publication: New York, NY: Lewis Historical Publishing Co., 1913
   Abbrev: New England Families
   Page: 1:457
8. Title: New England Marriages Prior to 1700
   Author: Clarence Almon Torrey
   Abbrev: Torrey
   Publication: Baltimore MD: Genealogical Publishing Co., 1985 & 1992
   Abbrev: New England Marriages
   Page: p. 29
   Text: William1 Backus (-1664, 1661?) & 1/wf (___); b 1635; ?Norwich, CT
9. Title: New England Marriages Prior to 1700
   Author: Clarence Almon Torrey
   Abbrev: Torrey
   Publication: Baltimore MD: Genealogical Publishing Co., 1985 & 1992
   Abbrev: New England Marriages
   Page: p. 29
   Text: William1 Backus (-1664) & 2/wf Anne (Stenton/Stetson?) Binhgam (-1670), w Thomas; ca 1659/60; Norwich, CT/Saybrook, CT