German fortification of Guernsey reduce the number and quality of troops required to defend the western ocean areas. Whilst the Luftwaffe and Kriegsmarine had their roles in protecting the islands from the Allies, the occupying forces put their main effort into land defences aimed at repelling a seaborne or airborne assault. The resulting construction work in the Channel Islands was extensive; it required thousands of workers and massive supplies of cement and steel. Tiny Guernsey received special treatment. It had the largest artillery pieces in the Channel Islands, tanks, and 12,000 troops: one soldier for every two civilians on the island, compared to France
Bailiwick of Guernsey was introduced above the "fiefs" and below the "Eschequier" Court in Rouen and comprised the Bailiff and four Knights; the court heard appeals and tried criminal cases. Otton de Grandson, then the Governor of the Islands, delegated the civil powers to two separate bailiffs for Guernsey and Jersey before he went on the Second Crusade to the Holy Land in 1290. This can be assessed as the date of first creation of the two Bailiwicks. Situated around , Alderney, Guernsey, Herm, Sark, and some other smaller islands together have a total area of and coastlines of about . Elevation varies