Sponsors at baptism; what age?

The concept of a baptismal sponsor or godparent developed gradually over time.  At one point, it was actually not allowed by the church, but in some places there could be quite a number of sponsors.  For a long time, there was no one set of guidelines as to the age or other qualifications of the sponsor, and different places had their own customs.  Various laws did develop about whether a sponsor had to be a relative of the child, and there were even laws forbidding a godchild to marry his/her godparent, or a parent to marry his/her child's godparent.  After the Reformation (when some Protestant sects rejected the whole concept, though larger churches like the Lutherans and Anglicans kept it), the Catholic Church revised its rules, and now a godparent has to be at least 16 years of age and a confirmed Catholic who has received communion.  It is permissible, though, for a non-Catholic to participate as a baptismal "witness", so long as there is at least one qualified godparent at the baptism.  Those rules would normally have been followed in 19th century Ireland.

Thankyou Kevin for this very detailed reply. It has been very helpful. 

Jennifer