a Roman Caesar or Augustus, known to us from medals only, and these struck after his death. They are very rare, but exist in all the three metals, bearing upon the obverse a head, either bare or radiated, with the legend DIVO NIGRINIANO; on the reverse, a funeral pyre, or an eagle, or an altar, or an eagle upon an altar, with the word CONSECRATIO. It has been conjectured that he was the son of Alexander, who assumed the purple in Africa, A. D. 311, and was soon after destroyed by Maxentius. There is not, however, a jot of evidence in favour of this hypothesis. (Eckhel, vol. vii. p. 520.)
[W.R]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890