Thomas Whittemore (January 2, 1871 – June 8, 1950) was an American scholar and archaeologist who founded the Byzantine Institute of America. His close personal relationship with Mustafa Kemal Ataturk, founder and the first president of the Turkish Republic, enabled him to gain permission from the Turkish government to start the preservation of the Hagia Sophia mosaics in 1931.
Thomas Whittemore was born in the Cambridgeport neighborhood of Cambridge, Massachusetts, on January 2, 1871. He earned a Bachelor of Arts degree in English Literature from Tufts College in 1894. He taught English Composition at Tufts for a year and then studied at Harvard Graduate School of Arts and Sciences. He also taught courses in the fine arts at New York University and Columbia University.
From 1911 until his death Whittemore served as American representative on the Egyptian Exploration Fund.
Whittemore worked in various capacities to provide relief to Russian refugees during World War I and following the Russian Revolution. He spent 8 months in Russia in 1915-16 and reported on conditions there when he returned to New York to organized shipments of supplies. He was a member of the U.S.-based Russian Relief Commission and a committee for war relief organized by Grand Duchess Tatiana Nikolaovna.
In 1930, Whittemore founded the Byzantine Institute of America, whose mission was to "conserve, restore, study, and document" the monuments and artworks of the Byzantine world. In 1931, Whittemore traveled with the Institute to Istanbul with the permission of Mustafa Kemal Atatürk to oversee the removal of plaster covering the Byzantine mosaics in Hagia Sophia. Of the radical and sudden transformation of Hagia Sophia from an active mosque to a secular museum in 1931 he wrote: "Santa Sophia was a mosque the day that I talked to him. The next morning, when I went to the mosque, there was a sign on the door written in Ataturk's own hand. It said: 'The museum is closed for repairs'"