The Byzantine Institute (commonly known as the Byzantine Institute of America) was founded by Thomas Whittemore in 1930. On May 23, 1934, the Byzantine Institute officially became the Byzantine Institute Inc., when it was issued a charter from the State of Massachusetts. Its mission was to conserve, restore, study, and document the Byzantine monuments, sites, architecture, and arts in the former Byzantine Empire.

In June 1931, Mustafa Kemal Atatürk, the first president of the Republic of Turkey, permitted Whittemore and the Institute to uncover and restore the original mosaics in Hagia Sophia, which had been covered in Islamic motifs since the church was converted into a mosque by the Ottoman Turks, in 1453. The Institute began the conservation and restoration campaign in December 1931.

In June 1950, Thomas Whittemore, founder of the Institute, died of a heart attack. Subsequently, Paul Atkins Underwood, a professor at Dumbarton Oaks, was appointed as the fieldwork director of the Byzantine Institute, a position he held until his death on September 22, 1968. Underwood supervised the restoration and conservation work at Hagia Sophia and Kariye Camii in Istanbul. Because of insufficient funding, the Institute officially ended its administrative and fieldwork operations in 1962 and transferred its assets to Dumbarton Oaks. In January 1963, Dumbarton Oaks and the trustees of Harvard University assumed all fieldwork activities formerly initiated by the Institute.

Image Collections and Fieldwork Archives, Collection MS.BZ.004—The Byzantine Institute and Dumbarton Oaks Fieldwork Records and Papers, ca. late 1920s–2000s, Dumbarton Oaks. [http://atom.doaks.org/icaatom/index.php/byzantine-institute-and-dumbarton-oaks-fieldwork-records-and-papers;isad]