While John FitzAlan acquired Arundel, Robert de Mohaut obtained the overlordship of the twelve fees constituting the honor of Halnaker, and certain other estates in the vicinity.

The unity of overlordship being thus lost, it may have appeared convenient to divide this district into two separate rapes, which would be of a similar size and nature to those in the rest of Sussex.

As Chichester was also a fortification in the Burghal Hidage, it is quite possible that it existed as a separate administrative unit in the Saxon era and was merged with neighbouring Arundel rape by William the Conqueror and given to Earl Roger of Montgomery.

The boundary between the Rapes of Chichester and Arundel started on the coast at the small stream dividing the parish of Pagham from that of Felpham.

[2] Once established it remained unaltered, the only change in the contents of the Rape being in 1844, when under the Counties (Detached Parts) Act 1844 the long narrow strip constituting North and South Ambersham was annexed to Sussex.