From the beginning of the 13th century, parishes are defined as sharply delineated territories. The parishioner's identity is determined in vertue of his living location, his home, into the parish's boundaries. However the rule might be different in Maine and Touraine. Some small villages located at the borders of 2, 3 or 4 parishes switch every year from a parish to another. This regular alternation is decided by custom, and is the result of compromises passed by owners of right. It enables an equal distribution of the parish's revenus and taxes (tithe). Far from beeing an oddity, the use of alternation within parishes is a common practice in the west of France for the priest's nomination.