Zosimus, Greek historical writer, nourished at Constantinople during the second half of the 5th century A.D. According to Photius, he was a count, and held the office of "advocate" of the imperial treasury. His New History, mainly a compilation from previous authors (Dexippus, Eunapius, Olympiodorus), is in six books: the first sketches briefly the history of the early emperors from Augustus to Diocletian (305); the second, third and fourth deal more fully with the period from the accession of Constantius and Galerius to the death of Theodosius; the fifth and sixth cover the period between 395 and 410. For the end of his period, 395 - 410, he is the most important surviving non-ecclesiastical source. The work, which is apparently unfinished, is believed to have been written between 450 - 502. The style is characterized by Photius as concise, clear and pure; other historians have judged his accounts confused or muddled, and valuable only because he preserves information from lost histories. The historian's object was to account for the decline of the Roman empire from the pagan point of view, and in this undertaking he at various points treated the Christians with some unfairness.

From an old 1911 encyclopedia

Zosimus is also the name of a pope.