The Transdanubian Reformed Church District became independent in 1595 under Bishop István Bejthe. Earlier its territory had belonged to the Győr and Veszprém Catholic Episcopates. It consisted of eight dioceses: Kőszeg, Vép, Körmend, Németújvár, Vízlendva, Pápa, Veszprém and Kiskomárom. The Outer Somogy Diocese separated from the latter two and joined the Danubian District from 1629; in turn, at the beginning of the 18th century the Inner Somogy Diocese was attached to the Transdanubian District. In 1710 its bishop, a Veszprém pastor named Sámuel Hodosi was expelled by Ottó János Volkra, Catholic Bishop of Veszprém, so until 1736 the district did not have a bishop. Then in accordance with the Carolina Resolutio it merged with the Somorja (Upper Danubian) District and the bishop of the latter, István Kocsi Major continued his service in the united church district, which henceforward was called “Transdanubian”. At first it also had eight dioceses: Pápa, Veszprém, Inner Somogy, Tata, Mezőföld, Komárom, Bars and Drégelypalánk, then in 1808 a ninth diocese, Őrség joined it. As a consequence of the Trianon Peace Treaty the northern part of the church district was annexed to Czechoslovakia and soon it formed an independent church district. The recent borders of the church district were fixed in 1952. Since then the Transdanubian part of Hungary has belonged to the district, with the exception of Baranya, Tolna and Pest Counties and the northern part of Fejér County.
The 1765 Adásztevel general assembly of the Tansdanubian Church District decreed to establish archives, stating: “A collection should be established. The dioceses (tractus) should have their own sections according to numbers, and the letters of the diocese should be conserved here like in an archive”. This archival collection did not have a permanent place, it was always held at the residence of the bishop of the time (Adásztevel, Kocs, Losonc and Dád).
In 1821 chief notary Ferenc Tóth granted his rich record collection to the archives of the church district and others followed suit. After having been elected bishop in 1827, Ferenc Tóth transferred the archives from Dad to his seat, Pápa, and made a catalogue prepared. The work lasted one and a half decade, in the end it was completed by Dániel Mórocza county-court judge. After the death of Ferenc Tóth in 1844 the archives were moved to the residence of the following bishops, at first to Kocs then to Révkomárom, and the records of the bishopric and the chief notary were handled separately again. After the death of Béla Széki chief notary in 1871, the chief notary’s records were placed in the library of the Reformed College of Pápa, where the documents were arranged by Professor István Rózsa. In 1874 the documents of the bishopric were transferred here as well.
The collected material was arranged by priest Mihály Szekeres and he moved it from the Seminary building to an old library of the Old College. From that time onwards the church district continuously had an appointed archivist, usually a college professor. During the First World War, between 1914 and 1918 the archives were temporarily moved to the Seminary building but the records got mixed up and were re-arranged in 1924 only by archivist József Pongrácz. In 1927 the material of the Pápa Diocese and in 1927 the material of the Tata Diocese were taken in by the archives of the district.
In 1935 Bishop Géza Antal made a separate archival building built at his own expense on the courtyard of the Seminary (Séllyei István Street). Nevertheless, the Second World War caused huge damage. The material was re-arranged from the 1950s by Dezső Trócsányi and Zsolt Kövy. During the Communist dictatorship the archival building as well as the Reformed schools of Pápa were nationalized, so in 1951/1952 the archives were moved to the church district building at 16 Jókai Street, then in 1969 it was moved to 17 Csáky László (then Teleki Blanka) Street. In 1958 the library and the archives of Pápa, then from 1972 the museum were fused by the Church and the unified organization was named “The Scientific Collections of the Transdanubian Reformed Church District”.