MAASSEN, FRIEDRICH. - Jurist and canonist, b. at Wismar on 24 Sept. 1829, d. at Wilten (Innsbruck) on 9 Apr. 1900. Born of non-Catholic parents, he converted to Catholicism in 1851.
After beginning as a lawyer, he became professor of Roman and canon law at Innsbruck in 1858, moving in 1860 to Graz and finally in 1871 to Vienna, where in 1883 he was elected rector of the University. Owing to his great renown as a jurist, he was a member of the Supreme Court of the Austrian Empire (Reichsgericht) from 1882 to 1899 and of the House of Lords. Together with F. von Florencourt he founded the Norddeutscher Korrespondent.
He wrote many works on Roman and canon law; among these should be mentioned Der Primat des Bischofs von Rom (Bonn 1853) and the Pseudo-Isidorstudien (2 vols., Vienna 1885); but the work that surpasses all the others, by reason of the depth of its investigation and its contribution to the history of medieval canon law, is the Geschichte der Quellen und der Literatur des canonischen Rechts im Abendland bis zum Ausgang des Mittelalters (I, Graz 1870). He also edited the Concilia aevi Meroviugici (in MGH, Leges, III).