Ranking as a pioneering force behind Chicago Architecture is one of the city's most venerable architecture firms, Holabird & Root; since the end of the 19th century up to the present day it has nurtured construction in the Chicago tradition. Holabird & Root were among the first to make the shift from self-supporting walls to the steel skeleton frame. In 1939, John Holabird Senior succeeded in bringing Mies van der Rohe to the city to head the Architecture Department of what is today's Illinois Institute of Technology: in the 1950s & 1960s it would be Mies who dictated the shape of Chicago's silhouette. Set against the century-long history of Holabird & Root's work, the story of development of Chicago's architecture as a whole comes vividly to the fore.