Flavius Valerius Severus died on 307-09-16.

Flavius Valerius Constantinus at Naissus (in modern Yugoslavia), Constantine was the son of Constantius Chlorus and his concubine Helena.

Constantine the great's full name in Latin was Flavius Valerius Aurelius Constantinus Augustus.

If you are referring to Constantine I (or the Great), his full name was Flavius Valerius Aurelius Constantinus Augustus. Augustus was the title of the emperors.

Flavius Valerius Aurelius Constantinus Augustus was found Constantinople as the new capital of the roman empire. Constantine chooses Byzantium as the new capital of the Empire and renames it Constantinopolis.