The Gotha Research Library preserves 521 mediaeval manuscripts produced between the 8th and 16th centuries in the European cultural area (shelf mark groups Memb. I; Memb. II; Chart. A; Chart. B).
They entered the collection thanks to the activities of the Ernestine dukes, especially in the 17th and 18th centuries. Some were family property, others spoils of the Thirty Years' War. Later further manuscripts were acquired through the help of resourceful booksellers such as the French Benedictine monk Jean-Baptiste Maugérard (1735–1815), who was Duke Ernst II's (1745–1804) main supplier for several years.
Numerous mediaeval manuscripts are decorated with elaborate illuminations, such as the “Sächsische Weltchronik” (Saxon World Chronicle; Memb. I 90; c. 1270) as the oldest vernacular universal history with 499 miniatures or “Der Welsche Gast” (The Italian Guest) by Thomasin von Zaerklaere (Memb. I 120) in a copy from 1340, richly decorated with 120 marginal illustrations.
The spectrum of codices that are important in terms of tradition and material includes inter alia
theological commentaries by early and high medieval scholars such as the Venerable Bede (672/3-735) and Petrus Comestor (c. 1100–1178)
saintly vitae and works of devotional practice
collections of law
the Aristoteles latinus
central works of classical Latin literature and grammar, rhetoric and arithmetic.
Medical recipes and home remedies or the Alexander novel are also part of the collection. Among the sole surviving material is the verse novel “Reinfried von Braunschweig” (Memb. II 42) from the 14th century.
Central texts of the major disciplines and the Seven Liberal Arts as the foundation of university education are represented in the collection. Sources regarding courtly culture and pragmatic knowledge in the Middle Ages can also be found here.