1115-1118 William son of Hacon appears in the Lindsey Survey. [1]
Willelmus filius Haconis In Cucualt vii b'. et dim' de rege de Ran[nulfo] Mischini et de Alano de Perci et comite de Moreton.
c 1115-18 William son of Hacon became under-tenant at Saleby soon after Alan de Craon succeeded his father Guy de Craon. Dudding states, [2]
When the Domesday Survey was made ... the larger part of the village of Saleby with Thoresthorpe was in the possession of Hugh son of Baldric. Shortly afterwards it was transferred to his son-in-law, Guy de Craon. At an early period, probably soon after Alan de Craon inherited the property, William son of Hacon became under-tenant at Saleby.
c 1141 William of Saleby attested a grant to Alan of Welton by William I de Roumare, earl of Lincoln, with his brothers Ralph and Richard. [3]
c 1150 William of Saleby founded the Gilbertine priory of Sixle. Dudding states, [4]
William son of Hacon, also called William of Hainton, and later, William of Saleby, was certainly the founder of the Gilbertine priory of Sixle, about the year 1150; though Dugdale's unfortunate guess that the founder was a Gresley has been adopted by every later authority.
A little investigation would have shown the improbability of this conjecture, for the interest of the Gresleys in Sixle was really very small. They were overlords of about a knight's fee in Hainton, which was held by the Saleby family, and of which the eighth part had been granted to Sixie priory long after its foundation. On the other hand William son of Hacon, Ediva his wife, and Thomas his son and heir, had by their charter given all their land in Sixle, namely a carucate, and the church of that village, to the nuns serving God there; also the site of a mill on the water of Tealby, two bovates of land in South Willingham, and five bovates of land in Nettleton with a sixth part of the church of Nettleton; but from the land in Nettleton they had to pay to the heirs of Rocelin two marks for the land in Sixle.
Some years later, 13 February, 1205-6, a final concord was made between John prior of Sixle and Jollan de Nevill concerning a carucate of land in Sixle with the advowson of the church, belonging to Jollan's fee, which William son of Hacon and Thomas his son and heir gave to the convent of Sixle. Jollan acknowledged the land and advowson to be the right of the convent of the gift of William and Thomas, to hold quit for ever of two marks annually for the scutage which that land owed, and for this the prior gave Jollan sixty marks.
[1] K. S. B. Keats-Rohan, Domesday People, A Prosopography of persons occurring in English documents, 1066-1166 (Boydell & Brewer Ltd, 1999), 83, in Appendix I, The Lindsey Survey, [GoogleBooks].
[2] Reginald C. Dudding, History of the Manor and Parish of Saleby with Thoresthorpe in the County of Lincoln (Horncastle: W. K. Morton & Sons, 1922), 10, Dudding states on page 4 that Alan de Craon was returned as holding land in Lindsey in 1115-18, [HathiTrust].
[3] K. S. B. Keats-Rohan, Domesday Descendants, A Prosopography of persons occurring in English documents, 1066-1166: II Pipe Rolls to Cartae Baronum (Boydell Press, 2002), 902, citing Lincs. Reg. Anq. vi, p. 99.
[4] Reginald C. Dudding, History of the Manor and Parish of Saleby with Thoresthorpe in the County of Lincoln (Horncastle: W. K. Morton & Sons, 1922), 10-11, [HathiTrust].