Many nonconformist chapels had a mother chapel that influenced the membership, growth and traditions of a congregation. Understanding the changes in a chapel, when it formed, who the ministers were and the doctrines taught may help a careful researcher find information to aid in research of a family or community. Ynysgau is one example of many chapels that played a central part in the community. Understanding when chapels split and combined will help a researcher determine which records may be the best candidates to search. The move of services from Cwmyglo to Ynysgau in Merthyr Tydfil about 1749 led to the building of another chapel closer to those who lived in Aberdare in 1751.
The chart below shows only a little of what should be learned about the chapels where research is being done. When it is seen that a chapel split off from the mother chapel it may explain why people seemingly disappear from the records.