Marcellus was the name of the most illustrious plebeian family of the Claudia gens. Plutarch states (Marc. 1) that the conqueror of Syracuse was the first person who bore this cognomen, but this is certainly a mistake. At what time it was first introduced we know not, but the first person of the name who appears in history is the consul of B. C. 331. [No. 1.]
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