Coinciding with the age of U.S. progressivism, courtyard apartments enjoyed heightened popularity in Chicago and its near suburbs from the turn of the century until the Great Depression. In fact, The strong U.S. economy not only helped Chicago enjoy its Bungalow Boom during the 1920s when the city produced 100,000 single-dwelling cottages but also led the tremendous growth in apartment construction nationwide; an average of 226,000 multiple-family dwelling units arose each year from 1924-1928.
The courtyard design fundamentally served to improve upon the dark, crowded -- often dilapidated, apartments associated with the Industrial Revolution. However, in truth, courtyard design dates back to the Roman Empire; both single- and multifamily homes, as well as government buildings and markets, were built around courtyards.
Meanwhile, during the Middle Ages and Renaissance, nobles enjoyed courtyards enclosed by castle walls, and monks often took advantage of central, outdoors spaces within monasteries.
In contrast, the castle design of Chicago-area 1920s apartments, including the Castle Tower Apartments in Evanston, did not include a fully enclosed courtyard. Instead, open space rather than crowded spaces stemmed from a societal shift associated with Progressive Era ideals, and the apartments built in the suburbs arose from Chicago's rapid population rise and concurrent urban crowding.
The explosive population growth in Chicago from the mid-nineteenth century to the 1920s included tremendous crowding and congestion. Hence, many people sought refuge by moving to the suburbs, such as Evanston, IL, an option that evolved due to a rapid transit system that connected Evanston to Chicago's downtown, created during the first two decades of the twentieth century.
While moving away from the crowded city was one thing, living in an apartment would only be deemed acceptable if the apartments showed no resemblance to their city counterparts. So, rather than bland designs and crowded spaces, the prevalence of courtyard and castle-style appearances emerged.