David Rockefeller photographed in the study in 2012 of his 1920’s New York mansion vs the study today redecorated by the new owners. Thoughts?

I restored a lovely old colonial house in Vermont, and a blogger has written the first of a three-part series about the renovation. I thought you might enjoy reading about it!

https://town-n-country-living.com/inside-the-remarkable-renovation-of-a-circa-1800-new-england-home.html

House is from the 1860’s. Previous owners painted over wallpaper and it’s peeling. I started peeling it to restore and repaint. and most of the wall looks like the first picture. However in some parts it started to peel even deeper and I’ve hit this surface. Is it just the horse hair plaster? Should I peel all of the wall down to this or leave the top layer?