According to historian Penny Petersen of Mapping Prejudice, Minnesota played a major role in this discriminatory practice. The first known racial covenant in the state dates back to 1910, a decade before such restrictions became widespread nationally. By the 1920s, developers such as Samuel Thorpe of Thorpe Brothers had incorporated racial covenants into numerous Minneapolis properties.
Thorpe also held leadership roles in the real estate industry, serving as president of what is now the National Association of Realtors. Under his leadership, racial covenants were codified into the organization’s ethics guidelines in 1924, leading to their proliferation across the country.
