The Institutum Batthyanyanum was the foundation of the Roman Catholic Bishop of Transylvania, Batthyany Ignac, born in a true family of aristocrats, intimate counselor of Maria Theresa and then of Joseph II, a foundation based in the former church of the Trinitarian monks in Alba Carolina Fortress.
As a great bibliophile and book collector, the Bishop of Transylvania transferred to Alba Iulia his entire book collection, which included, besides numerous other collections, the collection of the library of Cardinal Viena, Cristoforo Migazzi. The collection of the latter is an immeasurable legacy of western codons and icons, including the Carolingian Codex Aureus manuscript, the half of the Vatican Library with which it forms a whole, known as the Evangelical Das Lorscher. The Batthyaneum Library currently houses over 50,000 books, 19,000 documents, 1230 manuscripts and nearly 600 icons, invaluable witnesses of European and Transylvanian culture.
The building of the library, a former monastery of the Trinitarians, is a historical monument and was built in Baroque style between 1719-1738. Later, in 1792, Bishop Ignatius Batthyany, who purchased and arranged the building, gave him the role of a library, astronomical observer and diocese typography. Another important aspect of this architectural complex is found in the presence of the decorations “with elements defining the Transylvanian art at the end of the 18th century”, as art historian Kovacs Andras pointed out.
Today the Batthyaneum Library is owned by the Romanian State and is in the administration of the National Library of Romania despite the fact that the Roman Catholic Archbishopric of Alba Iulia makes great efforts to recover both the Library and the Institute of Astronomy, both nationalized by the State in 1949.