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.
It was the time in which Constantine the Great ruled Ancient Rome.
Constantine
Constantine is important to ancient Rome because he was the first emperor of Christianity.
Constantine
He was the first Christian ruler in ancient Rome/Greece.
This is a matter of discussion among some historians. Some say that Constantine called it New Rome, but people called it Constantinople in his honour and the name stuck. Others argue that he called it Constantinople and New Rome was one of the honorific tiles given to the city, such as the Eastern Rome, the Second Rome, Alma Mater, etc.
Jesus - although he never traveled to Rome and was not really part of Roman society he obviously was the ultimate source of ancient Christianity everywhere including Rome. ... alternatively you could name Paul - who was taken to Rome for trial an established the Christian Church there Constantine - the first "Christian" Roman emperor
Constantine was the first Christian emperor in 306AD and he made it the state religion.
When the Emperor Constantine the Great moved the capital of the Roman Empire, from Rome to the Ancient Greek city of Byzantium, in 330 AD, he renamed it Constantinople (city of Constantine) and made it the new capital of the Roman Empire. Because there could not be two capital cities with the same name, he called Constantinople the New Rome (Nova Roma).
Constantine was the first christian ruler for Rome.
The answer is the Arch of Constantine in Rome.
Constantine I