The collection of correspondence of Hüseyin Hilmi Pasha, who was the Grand Vizier at the time of the March 31st Incident, is an important source for researchers interested in late Ottoman history, the Committee of Union and Progress, the Balkans and Macedonia. Hüseyin Hilmi Pasha's official and personal correspondence is an important primary source for national and international political developments in the Balkans, especially during his Rumelia Inspectorate. The documents from this inspectorate period account for more than half of the collection.

This fond contains documents reflecting Rıza Tevfik's world of thought, the political events of his time, intellectual movements, and his relations with his environment and the world. Covering the years 1856-1997, the collection is organized in 32 folders and 921 files. It contains 3,998 documents of 12,978 pages, including correspondence with important people and institutions in Turkey and around the world, as well as manuscripts, photographs and newspaper clippings. The fond, which sheds light on the last period of the Ottoman Empire and the early years of the Republic, is a valuable source for research on this period.