Complex sentence: It preserved works such as Tacitus' "Annales", Ammianus Marcellinus' "Res gestae", Codex Fuldensis, and the monastery is considered the cradle of Old High German literature.
Split into simpler sentences: It preserved works such as Tacitus' "Annales", Ammianus Marcellinus' "Res gestae", and the Codex Fuldensis. The has the reputation of serving as the cradle of Old High German literature.