In studying the history of the Anglican Church in England I often find statements such as "In <date> the chapelry of St. So-and-So became a parish". In my experience, the <date> is just a year, never anything more precise, and there is no citation of any contemporary source document by an Anglican authority. If one wants to know whether a certain church was a parish church or a chapelry to another church at a certain time, what sort of document would one consult so as to have an authoritative and reliable scholarly source to cite? I'm sure that the rules changed over time, so I should say that the period I'm most interested in would be the early part of the 19th century. Let me offer my guess. The Wikipedia pages on Civil Parish, and on Ecclesiastical Parishes lead me to believe that the creation of a vestry was of critical importance. So maybe what happened is that, as the population in a chapelry grew, eventually its residents might want more independence in handling their own affairs, and be willing to shoulder the financial burden accordingly. So they would apply to the vestry of the mother church and ask if they could become their own parish. If the mother church's vestry agreed, then it would apply to the bishop of the diocese, and if the bishop also agreed, then it would be so. What had been a chapelry would now have its own vestry, responsible for its own funding and governance, able to appoint its own ministers independently of the mother church, be directly responsible to the bishop, and would thus have official status as a parish. If this is true, then the documents I should look for would be those in which the creation of the new vestry was announced. Can anyone versed in the Church's history in this respect enlighten me?
Although I am unable to answer your specific question I have an interesting anecdote to relate. I grew up in a church which had the official name of Jesus Chapel, St Mary's Extra, (otherwise known as Peartree Church). Queen Elizabeth the First planted a pear tree on the common land upon which the church is built, overlooking the river Itchen. As far as we know it was the very first church dedicated as a Church of England church, in 1620. There is no record of a purpose built church being dedicated by the Church of England previous to 1620. The service of dedication was written by the Bishop of Winchester, Lancelot Andrewes and sections of it were later included in the Book of Common Prayer 1662. It was originally a Chapel with a curate who had to donate all his fees to Ye Rector of St Mary's on the other side of the river Itchen. The chapel was built by Richard Smith for the parisioners of St Mary's, who lived on the east bank of the river and had suffered various injuries and deaths crossing the river in wintertime. It wasn't until the 1800s that the population of the fishing village of Itchen became large enough through urbanisation that the church gained the status of a parish church. Up until then the parishioners had to attend St Mary's on the other side of the river at least once a year at Easter or Whitsun. I shall try to make enquiries as to when it actually achieved Parish Church status and how that came about. It may be in the church records. .
Tiffy was just Itchen to be born there... I don't suppose they still have a pear tree, do they? If so, what variety of pear? I'm partial to Bartletts.
There are pear trees there but not the original one. They are not so long lasting as oaks and yews and Peartree Green is quite exposed high ground. The churchyard is now closed to burials since about 1920 and is surrounded by mature lime trees, some of which come down occasionally in gales. Actually my mother was itchen to move there when she married my father. I was 18 months old already when I moved there with her. .
Lime trees? Who would have thought? "And a partridge in a lime tree" doesn't have quite the same ring, this holiday season...
Ahh! but these are not the fruit trees that bear limes. They are huge and I think you American folk would call them linden trees. No partridges either, they nest on the ground I think. .
To answer the original question I think new parishes were created to accommodate changes in population. A church may have been built to serve a small community who lived quite far from the parish church in days before the car being a common mode of transport and people had to walk or used some form of horse-based transport. If the population served by that church grew, for whatever, reason it may be able ot seek parish status. Prior to the Industrial Revolution I would imagine this was not a common occurrence. Howver, during the Industrial Revolution many former small towns rapidly expanded. The increasing population of those towns and cities would have needed parishes. What is the exact process for creating a new parish? I admit to not knowing but am sure it has quite a few legal steps. Just as I don't know the process I don't know what documents you would need to find to discover the actual legal creation of a parish. Try posing another question in an appropriate sub-forum to discover if we have any [Church of England] historians on the Forum or if anyone knows of any you could contact.
At archive.org I found a book called "Parish Law" by Joseph Shaw written in the 1730s which contains some relevant information. On page 5 in Item 17 he says: And hence it is, that when it is a Question, Whether it be a Parish Church, or only a Chapell? It shall be decided by the Bishop's Certificate. Unfortunately there is nothing more about this Bishop's Certificate, but that, at least, is one kind of document that one could look for to decide the matter, at least for the period in which Shaw was writing. Then on page 6 Item 21 Shaw says: But making Rates alone without having other Parochial Rights, will not make it a Parish, though there was a Chapel there before the making the Statute, and though Divine Service was read there at that Time. Finally, on page 8 Item 1, he gives a definition of a parish that is useful in distinguishing it from a chapelry: From what has been said, a Parish, collectively taken, may be designed to be a Body of People living within a certain District, to which belongs a Parish Church, with a Right of Burial, and of having the Holy Sacraments duly administered there, with a Right of Tithes and other Church Dues, and of making Parish Rates, and choosing their own Parish Officers, etc., which Officers, with the Incumbent, by Order of the Vestry, have the Direction and Management of all the Parish Affairs and Business. So collecting rates and having a building for worship were necessary but not sufficient to grant Parish status. Also needed was a burial ground and a vestry and the usual officers and minister. If the people could put all that together, then, it seems, they could reasonably hope to obtain the Bishop's Certificate and elevate their chapelry to a parish. I think a lot of this changed under the Church Building Acts and the New Parishes Acts of the 19th century, at which time a board of commissioners could subdivide a populous parish into smaller parishes all at once. For an overview, see the online copy of Archbold's Parish Officer and Shaw's Parish Law, chapter 1.
I don't know how current you want your law but the first half of the eighteenth century is quite old. You must remember that at that time the parish was not just an ecclesiastical jurisdiction. It was also the local civil authority. Consequently, the law at that time will reflect this.