Over decades, the predecessor institutes of the IOS received extensive bequests from scholars. Since the IOS does not maintain a scientific archive, in 2017 it was decided to divest these materials and to keep only the libraries left by the scholars. In detail, in 2020 the papers of Otto Böss (1929–1994) and Hans Koch (1894–1959) from the holdings of the former Institute for East European Institute and the bequest of Carl Patsch (1865–1945) from the holdings of the Southeast European Institute were handed over to the Bavarian General State Archives in Munich; since 2018/19 the papers of Otto Hoetzsch (1876–1946) and the bequest of Hedwig Fleischhacker (1906–1978) and Hans Uebersberger (1877–1962) have been located in the archives of the Humboldt University in Berlin. Already in 2006, the Southeast European Institute handed over the “Coronensia” bequest of Friedrich Wilhelm Stenner (1851–1924) to the archive of the Honterusgemeinde in Brașov.
The following bequests are still located at the IOS:
Archive and Library of Erik Amburger
In addition to a card index of individuals containing 100,000 entries, the historian and genealogist Erik Amburger (1907–2001) bequeathed almost 3,000 genealogies and an extensive library.
Library of Irene Grüning
Irene Grüning (1900–1955) was born in Saint Petersburg and emigrated to Berlin after the revolution in 1917, where she became a student of Otto Hoetzsch. After World War II, she became a teacher at the University of Munich. Her library, acquired by the East European Institute (today the Leibniz Institute for East and Southeast European Studies) in 1956, consists of 500 volumes, mainly on Russian history.
Library of Gerasimos Kaklamanis
Gerasimos Kaklamanis (1940–2003) was born on the Ionian island Lefkada in Greece and spent most of his life in France and Germany. He studied mathematics, philosophy and history in Athens and Paris. Throughout his life he worked as a freelance writer. His literary work consists of seven books in the Greek language. The book ‟I Anatoliki Mesogeios Os Europaiki Istoria" (Tomos 1) can be regarded as his most important work.
The central concern of his academic and political work was to use his publications to draw attention to the particular importance of the Mediterranean region as a bridge between Europe and the Middle East. With critical and analytical questions, he addressed the region's interrelations and their consequences for global policies in the past, present and future. Because he often opposed the ruling political conditions in his home country, Kaklamanis, like many Greek intellectuals, spent most of his life abroad.
His writing activities also led him over 40 years to build up a private library with about 5,000 books, mostly on the subject of the Mediterranean region. The library consists of books in German (60 %), Greek (30 %) and French (10 %).
Library of Hans Koch
Hans Koch (1894–1959) was the first director of the East European Institute in Munich from 1952 to 1959. The historian and theologist from Lviv worked as a professor in Wroclaw and Königsberg. During World War II, he worked for the German authorities in Ukraine, which was fiercely fought over in campaigns characterized by genocide. His library consisting of 1,400 volumes (among which were 1,000 books and 400 bundles of brochures on all regions of East and Southeast Europe) was acquired in 1960 by the East European Institute (today the Leibniz Institute for East and Southeast European Studies).
Library of Carl Patsch
The scholar Carl Patsch (1865–1945) initially worked in Sarajevo, where he established the Bosnian-Herzegovinian Institute of Balkan Studies in 1904. In 1921, he succeeded Konstantin Josef Jirečeks at the University of Vienna. His 1,400-volume library, acquired in 1956 by the Institute for Southeast European Studies (today the Leibniz Institute for East and Southeast European Studies), mainly consists of literature on the regions of the Western part of the Balkan Peninsula.
Library of Franz von Scheiger
In 1962, the library of the Institute for Southeast European Studies (today the Leibniz Institute for East and Southeast European Studies) acquired the 500-volume bequest of the engineer and diplomat Franz von Scheiger (1891–1960). The focus of his collection was on the history of Albania and its neighboring countries. The collection also included numismatic literature.
Library of Fritz Valjavec
Fritz Valjavec (1909–1960) worked at the Institute for Southeast European Studies from 1935 and was its director from 1955 until his death. He had great influence not only on the history of the Institute for Southeast European Studies but also on Southeast European studies as a discipline. For instance, he established the Southeast Europe Association (SOG) and the journal ‟Südost-Forschungen". During World War II, he worked for the intelligence service in Bukovina. His library (2,300 volumes) reflects the research areas of his scholarly life. It comprises literature on the history of the countries of the Habsburg Monarchy, focusing especially on the German components of the populations.