In the historical accounts of Orderic Vitallis he identifies the origins of the Tosny family
as being Scandinavian and related to the Dukes of Normandy.  He states that Roger de Tosny,
then Lord of Tosny and Conches, was “of the line of Malahulc uncle of Rollo the Duke”.

Raoull II of Tosny, his brother Robert de Stafford and their cousin Robert de Tosny all took
part in the 1066 Conquest of England and were rewarded with property.
Raoull II was given the baronies of Flamstead and Wrethamthorpe.
Robert de Stafford took possession of much of Staffordshire and build Stafford Castle.
Robert de Tosny became Robert of Beauvoir and Lord of Belvoir including the land of Horninghold.

The family became embroiled in the conflict between Empress Mathida and King Stephen following
the death of King William I.  In 1204 Roger IV of Tosny lost his continental fiefdoms as a result of
his support for King John and thus the family had to withdraw to England.
In 1309 the Tosny male line became extinct.
The duchy of Normandy in the second half of the
11th century, with the principal castles
of the house of Tosny (in black)

Tosny is a small town of 600 residents in the Eure
Department in Haute-Normandie, some 10 miles
South of Rouen.