According to the Rolls of the Norman Exchequer, in 1180 Jersey was divided for administrative purposes into three ministeria: , and (possibly containing four parishes each). Gorroic is an old spelling for Gorey, containing St Martin, St Saviour, Grouville and St Clement; Groceio could derive from de Gruchy, and contains St John, Trinity, St Lawrence and St Helier; and Crapoudoit, likely referring to the stream of St Peter's Valley, contains the remainder of the parishes in the West. This was a time of building or extending churches with most parish churches in the island being built/rebuilt in a Norman style chosen by the abbey or priory to which each church had been granted. St Mary and St Martin being given to Cerisy Abbey. By Norman times, the parish boundaries were firmly fixed and remain largely unchanged since. It was likely set in place due to the tithe system under Charlemagne, where each property must contribute to the church, so each property would have had to be established within a parish. The parish system is much more important in Jersey than in England or post-Napoleon France.:15