Köpke, in his 'Anfänge des Königthums bei den Gothen' (Berlin, 1859), has condensed into a small compass a large amount of useful disquisition on Cassiodorus and his copyist Jordanes. The relation between these two writers was also elaborately discussed by von Sybel in his thesis 'De Fontibus Libri Jordanis' (Berlin, 1838), and by Schirren, in his monograph 'De Ratione quae inter Jordanem et Cassiodorum intercedat' (Dorpat, 1885). The latter, though upon the whole a creditable performance, is disfigured by one or two strange blunders, and not improved by some displays of irrelevant learning.
Von Schubert, in his 'Unterwerfung der Alamannen unter die Franken' (Strassburg, 1884), throws some useful light on the question of the date of the early letters in the 'Variae;' and Binding, in his 'Geschichte des Burgundisch-Romanischen Königreichs' (Leipzig, 1868), discusses the relations between Theodoric and the Sovereigns of Gaul, as disclosed by the same collection of letters, in a manner which I must admit to be forcible, though I do not accept all his conclusions.
Mommsen, in his paper 'Die Chronik des Cassiodorus Senator' (Vol. viii. of the 'Abhandlungen der Königlich Sächsischen Gesellschaft der Wissenschaften;' Leipzig, 1861), has said all that is to be said concerning the unfortunate 'Chronicon' of Cassiodorus, which he handles with merciless severity.
To say that Ebert, in his 'Allgemeine Geschichte der Litteratur des Mittelalters im Abendlande' (Leipzig, 1874), and Wattenbach, in his 'Deutschlands Geschichtsquellen im Mittelalter,' tell us with fullness and accuracy just what the student ought to wish to know concerning Cassiodorus as an author, is only to say that they are Ebert and Wattenbach. Every one who has had occasion to refer to these two books knows their merits.
Passing from German literature, I regret that I am prevented by ignorance of the Dutch language from forming an opinion as to the work of Thijm ('Iets over M.A. Cassiodorus en zijne eeuw;' Amsterdam, 1857), which is frequently quoted by my German authorities.
Gibbon of course quotes from the 'Variae,' and though he did not know them intimately, he has with his usual sagacity apprehended the true character of the book and of its author. But the best account of the 'Various Letters' in English, as far as I know, is unfortunately entombed in the pages of a periodical, being an article by Dean Church, contributed in July, 1880, to the 'Church Quarterly Review.' There is also a very good though necessarily brief notice of Cassiodorus in Ugo Balzani's little volume on the 'Early Chroniclers of Italy,' published by the Christian Knowledge Society in 1883.