William Carroll "Cal" Roy (1851-1916) and Annie (Stanley) Roy (1851-1925) bought this Bouldin mill site in 1894 from Powhatan Bouldin, heir of James E. Bouldin (1796-1876), the original owner. It was converted into a home, and here the Roy's reared children Robert E. "Rob," Addie M., Jessie, Adele and Inca. The family sold the home in 1939 to Ernest Randolph Hardin (1902-1987) and his wife, Maurine (Underwood) (1900-1946). The Hardins, both drama professors, eclectically restored the rubblestone house with architectural antiques such as a floor from Austin's Driskill Hotel and decorative ironwork. In the 1940s, they added a weathervane marked "Millbrook" to the carriage house; this gave the property its name.