Spain did not establish diplomatic relations with the United States until 1790, after the ratification of the 1783 Treaty of Paris ending hostilities between the United States and the Kingdom of Great Britain. Diplomatic relations were broken off from 1808 to 1814 over American occupation of West Florida, and again from April 1898 to April 1899 during the Spanish–American War.
Beisner, Robert L. American Foreign Relations Since 1600: A Guide to the Literature. Santa Barbara, Calif.: ABC-CLIO, 2003.
Hodges, Allan A. and Hodges, Carol A. Washington on Foot: 23 Walking Tours of Washington, D.C., Old Town Alexandria, Virginia, and Historic Annapolis, Maryland. Washington, D.C.: Smithsonian Institution Press, 1980.
Pennsylvania Avenue Scenic Byway: Corridor Management Plan. Department of Transportation. Government of the District of Columbia. April 2006.
World Almanac and Encyclopedia. New York: Press Publishing Co., 1901.