The holdings 18 of the Mainz City Archives comprise a part of the written records of the old Electoral University of Mainz, founded in 1477 and existing until the beginning of the 19th century (other parts reached the State Archives of Darmstadt, Wiesbaden and Würzburg in the 19th century). The Mainz fragmented holdings came into the possession of the city together with the transfer of the university library by decree of the French Minister of the Interior in 1803/05. Among them are the statutes of the university as well as protocol books of the individual faculties, but also documents on the financing of the chairs or the coat of arms of the rectors from the university register.
The total of 61 archive record units were digitised in 2017 by the Service Centre for Digitisation and Photo Documentation of the University Library and linked to the title records in the FAUST database of the City Archive.Coat of arms of Rector Karl Heinrich von Metternich from 1664 from the matriculation book of the University of Mainz (18/182). The plates with the coats of arms of the rectors cut out at the beginning of the 19th century (presumably by Professor Franz Joseph Bodmann of Mainz) remained in Mainz, while the matriculation books handed over to the State Archives in Darmstadt were burned there in an air raid during World War II.