My thanks to Amos & Foolestroupe for the answer. And here I thought nuns had nun. Seems I've been wrong.

An Irishman is lamenting his not getting the nomination for alderman. Blaming it on his lack of schooling, he tells his wife if it weren't for you & the children I'd have had more time for my education. You held me back Brigid. "Held you back is it?" bristles the wife; "If you'd paid as much attention to your prayer book as you did to my bare ass, you'd be Pope by now."