In the search for Mary Kelly

I came across this:

Old Irish naming conventions

For sons

The 1st son was named after the father's father.
The 2nd son was named after the mother's father.
The 3rd son was named after the father.
The 4th son was named after the father's eldest brother.
The 5th son was named after the mother's eldest brother.

For daughters

The 1st daughter was named after the mother's mother.
The 2nd daughter was named after the father's mother.
The 3rd daughter was named after the mother.
The 4th daughter was named after the mother's eldest sister.
The 5th daughter was named after the father's eldest sister.

Which should assist in the quest for the illusive Mary.