a Roman senator in Nero's reign, was involved with others [FABATUS CALPURNIUS] in the charge of being privy to the crimes of Lepida, the wife of C. Cassius, A. D. 64. Marcellus eluded punishment on this occasion, but he was put to death by Galba's order in Spain, A. D. 68 (Tac. Ann. 16.8, Hist. 1.37), probably as a partisan of Nero's. (Comp. Plut. Galb. 15.)
[W.B.D]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