Encouraged by William IV., duke of Bavaria, he began to write the Annales Boiorum, about 1517, and finishing this book in 1521, undertook a German version of it, entitled Bayersche Chronik, which he completed some years later.
The Annales, which are in seven books, deal with the history of Bavaria in conjunction with general history from the earliest times to 1460, and the author shows a strong sympathy for the Empire in its struggle with the Papacy.
The Annales were first published in 1554, but many important passages were omitted in this edition, as they reflected on the Roman Catholics.
For the earlier part he used Widukind's Res gestae Saxonicae, the Annales Quedlinburgenses and other sources; the latter part is the result of personal knowledge.
For the earlier period their authorities were state and family records - above all, the annales maximi (or annales pontificum), the official chronicle of Rome, in which the notable occurrences of each year from the foundation of the city were set down by the pontifex maximus.
