The Dietrich ballads, which are part of the Germanic heroic tradition, are primarily attested in Scandinavia in the form of various medieval texts. Most notably, they are found in the following sources:
The Old Norse sagas: The Dietrich ballads are often referenced in the Saga of the Volsungs and other sagas that recount the tales of heroes and legendary figures.
The Eddaic poems: Some of the ballads are preserved in the Poetic Edda, which is a collection of Old Norse poems from the medieval manuscript Codex Regius.
The Skaldic poetry: This form of poetry, which was composed by skalds (court poets) in Scandinavia, also contains references to Dietrich and his exploits.
Danish and Swedish ballads: Various ballads and folk tales in Denmark and Sweden recount the adventures of Dietrich and his companions, reflecting the influence of the Dietrich legend in Scandinavian folklore.
The Dietrich ballads are significant in understanding the transmission of Germanic heroic legends across cultures, particularly how they were adapted and integrated into Scandinavian literary traditions. If you are looking for specific manuscripts or collections, the Codex Regius and various saga texts would be key sources to explore.