There’s an interesting passage about child-naming customs in Éamon Kelly’s autobiography The Apprentice (Marino Books, 1995). Kelly is recounting his childhood near Killarney in southwest Ireland, and the time he spent in his father’s workshop playing with pieces of wood:
I sat in the shavings and listened to the men who came with jobs for my father. They all spoke to me and those who knew my grandfather were surprised that I wasn’t called after him. The custom then was to call the first son after his father’s father and the second son after his mother’s father. The same rule applied to the first two girls. They were called after their grandmothers. If you walked into a house at that time and there were two boys and two girls in the family and you knew their grandparents, you could name the children. Both my male grandparents, who were inseparable friends, objected to my father’s and mother’s marriage. They claimed there was a blood relationship, though fairly far out, and the slightest trace of consanguinity had to be avoided. My mother was very upset by this attitude and called me after my father to annoy the old man. My father’s Christian name was Edmund, Ned to everybody, and so was I.
The name Éamon came later, when Kelly was a carpenter’s apprentice (hence the book title) working with his father. Since both were called Edmund/Ned, confusion arose when either was hailed, so someone took to calling the son Éamon. He remained Ned to his family and neighbours, but Éamon was the name by which I first knew of him.
I’ve written before about Éamon Kelly in his seanchaí (storyteller) guise, after coming across a couple of clips of him on YouTube. That post has additional resources on Kelly’s life, for anyone interested.
The custom he describes lives on but seems much less prevalent than it was a century ago – though my sister was named after our maternal grandfather, in a nice inversion of the tradition. I was named after my uncle, who was (I think) named after my granduncle. I’d be interested to hear who you were named after, if anyone, or what other naming traditions are in your family or area.