From Foundation for Medieval Genealogy, http://fmg.ac/Projects/MedLands/NORMAN NOBILITY.htm

ROBERT [I] de Tosny (-[1088]).  His connection with the Tosny family is confirmed by the charter dated 1063 which records the consent given by "Rotbertum de Toeniaco, avunculum domni Johanni monachi nostri, filii Widonis de Valle" to the donations by the latter to Marmoutier, authorised by "Berengerius filius eius"[3095].  “Robertum de Belvedeir---et A[dela]. uxor eius” founded Belvoir priory, Lincolnshire by charter dated to [1076][3096].  After the death of his wife Adela, Robert de Belvoir donated “land in Sapertune” to Belvoir priory, Lincolnshire, with the consent of "his sons William and Geoffrey"[3097].  Domesday Book records “Robert de Tosny” holding Great Rissington, Horton and Sapperton in Gloucestershire; several properties in Northamptonshire; properties in Leicestershire; North Dalton and Naburn in Yorkshire; numerous properties in Lincolnshire[3098].  m ADELAIS, daughter of --- (-before 1088).  “Robertum de Belvedeir---et A[dela]. uxor eius” founded Belvoir priory, Lincolnshire by charter dated to [1076][3099].  “Agnes de Toteneio” confirmed the donation to Belvoir priory, Lincolnshire by "pater meus Robertus de Toteneio et mater mea Adelais", by undated charter[3100].  Robert [I] & his wife had six children: Berenger, Guillaume, Geoffrey, Albreda, Adelise, and Agnes.