The Rookery was built in 1887–1888 by the architectural partnership of Daniel H. Burnham and John Wellborn Root, known as Burnham and Root. Making prodigious use of light and ornamentation, Root and Burnham designed a central light court to serve as the focal point for the entire building and provide daylight to interior offices. Rising two stories, the light court received immediate critical acclaim. Frank Lloyd Wright was a young architectural assistant working with Adler and Sullivan at the time the Rookery was built in 1886. Architect Daniel Burnham was a friend of Wright patron Edward C. Waller. Waller managed the Rookery; Wright had his offices in the building in 1898–1899. In 1905 Wright received the commission to redesign the lobby in the building; at the time considered the grandest in Chicago. Wright's work on the Rookery recast the entryway in his Prairie style and added a sense of modernity through his simple but effective lighting design. Wright's work on the Rookery is his only work on any building within the downtown cityscape. Among Wright's most significant alterations was the addition of white marble with Persian-style ornamentation.