The present paper discusses the person and literary achievements of Claudianus Mamertus as seen by his fellow writer and friend, Sidonius Apollinaris. In his extant writings, Sidonius presents a sympathetic and, indeed, impressive image of his friend as both a devout member of the Christian community and an outstanding intellectual. Both the letters to Mamertus and the eulogy written after his death testify to the friendship between the two writers, and the intellectual, spiritual, and personal qualities of Claudianus Mamertus. Sidonius’ works concerning Mamertus are often analysed to underscore the philosophical and theological character of Mamertus’ work; yet their elegant form and their deep connection to cultural tradition deserves also an analysis from a more aesthetic, literary point of view.