Robert P. and Mary Gray Lamb Strathearn purchased about 15,000 acres of the old Spanish Rancho and built their Victorian-era farmhouse into the front of the Simi Adobe in 1892. Possibly the thick walls of the old adobe reminded them of their home country, Scotland. The adobe rooms were used for kitchen and dining room, and the framed structure contains a double parlor, office and four bedrooms.
Robert P. and Mary Strathearn had seven children: Bert, Jim, Jessie, Marion, George, Isa and Dave.
There were once corrals, barns, a blacksmith shop and many other ranch features nearby. This was called the Home Ranch, and the part of the Strathearn lands toward Moorpark was called the Middle Ranch. The Strathearns were mostly known as cattle ranchers. All the generations were community leaders.