when the new wing broke away from the old mansion

that’s the tile of a “short story about Europe and America” by Jonathan Franzen, in today’s Guardian. Here’s the opening
“Once there was a mansion in which there lived five brothers. The four oldest brothers, who had played and fought and survived the diseases of childhood together, lived comfortably in the beautifully furnished older wing of the mansion.
The fifth brother, Joseph, was much younger. By the time he came of age, there were no comfortable rooms left for him, and so he was given the raw rooms in the mansion’s newer wing. Joseph was a strange, solitary, somewhat frightening child, and although his brothers loved him, they were relieved to have him out of their hair.”
Read on.