As commented above, in 1020 Duke Richard II divided Guernsey diagonally in two halves, granting the south and east to Néel, Vicomte of the Cotentin, and the west to Anchetel, Vicomte of the Bessin. The Clos du Valle was apparently wasteland. The two initial fiefs had some vicissitudes but by the time of the conquest of England both had returned to the families of the original holders.

Evolution of Fief du Bessin:
The Fief du Bessin consisting of the Vintaine de L’Epine, and the parishes of the Castel, St. Saviour’s and St. Pierre-du-Bois, became known as Fief Le Comte in 1120 when Ranulf the “Vicomte du Bessin” was created Earl of Chester. During the 12th century the fief was split into sub-fiefs: Fiez Rozel, Fief Longues, Fief Suart and Fief Sotuas. The Fief San Michel was originated in a donation of non-arable wasteland to the monastery of that name. After 1204 the fief Suart divided in two parts, one went to the crown while the rest was named fief Reveaux. The half of the Fief Suart retained by the Crown while the other half given to the Revel family led to the emergence of the Fief de Gohiers, Fief de la Pomare and others.
Agricultural developments and sales in the Fief Le Compte originated new sub-fiefs such as Fief Groignet, Fief Carteret, Fief Grantez or Fief Videclin. Similarly, land disposals from St. Michel accounted for the Fief Saumarez and Fief Jean du Galliard.

Evolution of Fief du Cotentin:
After the Battle of Val ès Dunes (1047), Duke William II created and granted several ecclesiastical fiefs. From 1144 to 1150 the whole island belonged to Geoffrey of Anjou. The wasteland of Fief du Cotentin as a part of Geoffrey possessions became under his son Fief Le Roi. New sub-fiefs originated during the 11th and 12th centuries like Fief Aux Fay and Fief Burons. The Fief Au Fay was held by payment of a pair of silver spurs and the Fief Burons by payment of a pair of gilded spurs. Both were combined as the Fief des Eperons (spurs) with the duty of payment a pair of silver-gilt spurs.
After 1204 the Crown got some territories form previous Norman holders that decided to render homage to France, thus loosing their island territories. That is the origin of some fiefs such as Fief des Bruniaux, Fief Au Marchant, and Fief Hailla. Fief de Sausmarez originated in the Fief Barneville. From St. Martin’s and associated to the defence of the Church originated Fief de la Velleresse (velleresse from veiller = keep a watch on the coast, having this obligation)
From fief Le Roi originated Fief de Rozel formerly held by the Cotentin family de Rosel which passed to the Crown in 1204 together with the fief granted by Duke William II to the Abbey of Marmoutiers. Geoffrey of Anjou created about 1150 when he was developing his plans for the invasion of England two military fiefs De Vaugrat and Bruniaux in St. Sampson’s parish. Also from this parish is Fief Anneville granted by Henry III to Sir William de Cheny in 1248.

There are 24 private Seigneurs:
1-Le Comte, Bruniaux-de-Nermont (*), Philippes (*), Cour, Grantez, Longues, Reveaux, Rozel, Fouquees, Bequepee, Chapelle-de- St-Georges, Saumarez au Castell, Coltons, Gohiers, Fortescu, Janin Besnard, Cantereine, Guillot Justice, Bouvee Duquemin.
2-Sausamez (*), a Saint Martin, Hailla (1/3)
3- Fantome (*), Domaine-de-Dom-Hue
4-Rohais (*)
5-Groignet
6-Blanchelande (*)
7-Canely (*),
8-Anneville (*)
9-Maumarquis (*)
10-Henry de Vaugrat (*)
11-Bruniaux (*) a Saint-Martin
12-Eperons
13-Beuval, Massy Gros.
14-Fauville
15-Sainte-Helene
16-Carteret
17-Lucas Arnault & Dom Jean Le Moigne
18-Videclins
19-Riviere
20- Thomas Blondel
21-Robert de Vicq
22-Marchant
23-Beauvoir
24-Cocq.

(this means 24 private Seigneurs totalling 46 Seigneuries)

The Fief de Beuval is hold by six persons and the Fief de la Riviere is hold by nine persons.