The ecclesiastical ordinance made by King Edgar and his Witanagemot at Andover, c. 970, was the first step in law taken in England to effect the transition from the old baptismal churches with their districts to the modern parish churches and parishes.
These churches had been originally built and endowed by laymen as oratories, and districts had been attached to them, the size of which was generally determined by the extent of the lands of the lay founder in the neighbourhood, which were intended to receive benefit from the foundation.
The priest was nominated by the lord or patron and received investiture from him, and not from the Bishop, until the 12th century, when this practice was prohibited by the third Lateran Council, 1179-80.
From some of the earlier London records one obtains the impression that the division into parishes was not very strictly carried out in the 10th and 11th centuries. The churches are often referred to as if they were private property served by private chaplains, with no parishes attached to them, and the parish prior to that time had been the bishop's cure of souls, or " administration."
By the middle of the 12th century, however, the notices of parishes become more frequent and lists of parishes are given from time to time in the City records.
The parishes in most cases were independent of the ward boundaries, but their boundaries were probably in many instances determined by the ownership of the land.
The number of parishes has varied somewhat from time to time, as shown in the article on Churches (q.v.), and it is probable that in the 10th or 11th centuries some of the larger parishes were subdivided and additional churches erected to provide for the ever increasing population of the City.
A Dictionary of London. Henry A Harben. 1918.