Baptismal witnesses were often close relatives or friends of the parents of the child. Knowing their associates and relatives can help you prove their identity and parentage.
You should look at baptismal witnesses from both sides:
- Check the people your ancestors chose as baptismal witnesses for their children
- Check for whom your ancestors acted as baptismal witnesses.
Most researchers do the first, since the information is there when they look up all the children. Fewer researchers do the second, since they think this is less relevant or the information may be more difficult to find. Baptismal witnesses are not always indexed. Finding out for whom your ancestors acted as baptismal witnesses may require browsing the baptismal registers of the town where they lived, and even of surrounding towns. But this will give you a new list of associates who may well be relatives, and may be the key to unlocking their identity and parentage.