The document summarizes the history of the Ansley Wilcox Mansion located at 641 Delaware Avenue in Buffalo, New York. It details that the mansion was originally built in 1840 as officer's quarters and later purchased in 1883 by Dexter Rumsey as a wedding gift for his daughter. Theodore Roosevelt was inaugurated as President in the mansion in 1901 after the assassination of William McKinley. The house took on additional uses over time and was declared a National Historic Site in 1966.