The Bishopric of Eger was founded by Saint Stephen of Hungary, it had already existed in 1009. Its territory was the biggest of the Hungarian bishoprics. In the first period it consisted of the Heves (Újvár), Külső-Szolnok, Borsod, Abaújvár, Zemplén, Ung, Ugocsa, Szabolcs, Bereg and Zaránd counties; later Sáros, Szatmár, Kraszna, Torna, Máramaros counties and the Jászság also belonged here. Before the foundation of the Várad Bishopric the Bihar parts also belonged to Eger; moreover, the Archdeaconry of Zsomboly (Pankota) belonged to Eger even after that, until the mid-18th century. In the 18th century the question of division of the huge
diocese arose repeatedly. Finally it took place in 1804, after the death of Bishop Esterházy, when Pope Pius VII established the Kassa and Szatmár Bishoprics and at the same time he promoted the Eger Bishopric to Metropolitan Archdiocese.
The medieval archives of the bishopric did not survive; only the “Saint John books”, containing the serfs’ duties, were preserved from the second half of the 15th century. The Holy See Protocols begin from 1600; the church government document series that may be described as continuous begin from the beginning of the 18th century; from the earlier period only a few 17th century documents are in the archives. From 1745, when Archbishop Ferenc Barkóczy took office, the volumes of the Holy See Protocol volumes were used as letter copying books. In 1766 Bishop Károly Eszterházy at first entrusted two Jesuits then one of his priests, Ignác Torner with the classification of the documents. As a result of the efforts of Eszterházy and his two successors, Mátyás Kotuts and István Fangh, in 1778 the economic and in 1779 the ecclesiastical archives were set up, both of them in thematic order, with registry books.
In 1804, when the Kassa and Szatmár Dioceses were established, the archival holdings concerning the detached parishes (among others the canonical visitation protocols) were selected and removed, only the protocol volumes remained in Eger. Thus the size of the archives decreased by half, so in 1805 the remaining material was classified into new groups of material. The church government and economic documents that occurred later were treated as a separate unit called “new archives” (Archivum novum); at first with current number registration and later in compliance with the subject areas elaborated by archivist József Hangony between 1818 and 1830. From the 1770s the documents were kept in the archiepiscopal palace, in a room built for archival purposes; only the documents from the period after 1923 were placed in a separate repository in 1954 (at the time of the dual administration of the archives).
The chapter archives are not preserved by the Archives of the Archdiocese, because the documents of the place of authentication were nationalized after 1950, and its private archives were given as a deposit to the Archives of Heves County, too, together with the economic archives of the Archiepiscopate and of the Seminary.