The Roman Marcus Constantinus born 441 bc died his first death in 390 bc in the defense of Rome. Soon after he became a noted General in the Roman Centurion Legion, winning the Battle of Actium, traveled to Egypt and falling in love with fellow Immortal Nefertiri. He also had saved his friend Remus, a slave and advisor to Petronius, from a painful cruixifiction and helped him escape the Empire.
He continued his career in the Legion, reluctantly accepting a student named Ceirdwyn who had fallen against his men on the battle ground, also having to pose as a slave before she returned to Brittania.
His most recent career includes as the Curaetor of the National Museum of Antiquities in Paris as witnessing firsthand the fall of rome had made him wish to preserve history to make up for destroying so much of it. His chief exhibits includes a collection representing peoples and cultures who had fallen and were forgotten because the Roman Empire.
Certain peices were stolen in 1998. These peices were Sumerian artifacts for the use of an archaic occult ceremony and following them brought Marcus as well as his assistant Dr. Amy Zoll to Seacouver where he reunited with an old friend and lover, Methos. He wasn't aware of the strength of Amy's feelings or that she was also his Watcher until both were explained by his old friend. As the artifacts were recovered, he grew closer to Amy, eventually entering into a more personal relationship and marrying her some time after their return to Paris.
Marcus returned to his position at the Museum, living out the years in relative quiet.