Emperor Constantine's family is referred to by scholars as the 'Neo-Flavians' or New Flavians. This is not due to the fact that those scholars have traced back Constantine's descent from the Flavian Dynasty of the 1st century, but because members of the Constantine's family used the name 'Flavius'; as if a rebirth of the earlier Flavian Dynasty.
Scholars have thought that this was done in an attempt to show themselves triumphant in ways that the earlier Flavian Dynasty had been, and not because they were actually descended from the Flavian family. But Emperor Constantine's family had used the name Flavius because they knew of their descent from those earlier Flavians, but the general public was kept in the dark about this.
During the reign of Emperor Constantine, the decision was made to translate all of the biblical texts into Latin, because of what the Greek texts revealed. Constantine had a hand in commissioning that translation, and the task was done by 'St. Jerome'. We are told, in the form of two contradictory accounts, one by Christian historian 'Eusebius', and the other by an individual named Lactantius, a tutor to Constantine’s son, that Constantine saw a "vision" in the sky which led to his conversion to Christianity. Eusebius says that Constantine saw this vision in 312 CE, just before the Battle of the Milvian Bridge, which was essentially a battle between Constantine and Emperor Maxentius over the throne of Rome. Constantine looked up to the sun before the battle and saw a cross of light above it, and with it, a message saying 'in this sign, conquer'. Lactantius, however, says that Constantine and his army saw a great cross in the sky whilst in Gaul, before setting out towards Rome. Are Lactantius and the famous "bishop" 'Eusebius of Caesarea' reliable, no. How do we know the above really happened? we don't.
Many people, including scholars, who have researched the history of Christianity, have come to the opinion it didn't exist until the time of Emperor Constantine, which has led some to conclude that it was created by him. It didn’t really exist before Constantine’s time, but, those behind the creation of this religion were his ancestors, what Constantine did when he became emperor, was revive it. There is really no good reason to believe Constantine converted to Christianity because of faith, no matter how often an authority in the world of academia says otherwise.
Emperor (Julius) Constantius Chlorus (father of Emperor Constantine & of Julius Constantius I), ruled from 305-307 CE, and he was co-emperor with Galerius. Emperor Constantine was the son of Emperor Constantius Chlorus & Helena and ruled from 307-337 CE. Other important relatives include Tacitus, Emperor Trajan, Pliny The Younger, and Suetonius (Antoninus Pius). But with the knowledge that these individuals are related to Arrius Piso, this information can shed new light on another argument for Christianity existing before and during Nero’s reign. These are the mentions of ‘Chrestiani’, whose leader is ‘Christus’/‘Chrestus’ by Tacitus, who was related to Arrius, and even uses his alias names when describing events in history. If Tacitus was related to Arrius and used his various alias names within his literature, then the mention of ‘Chrestiani’ and ‘Christus’ and the persecution of Christians by Nero, can logically be seen as a pretense, making something that is not the case appear true, and an example of what can be called propaganda against an emperor that angered the aristocracy of Rome, which contributed to his assassination.
Emperor Constantine is made into a "new Jesus", by the Church Father 'Eusebius', who was Julius Constantius I (Constantines's half-brother). Emp. Constantius Chlorus used the name 'Eusebius', as "Pope Euesebius", so we begin our count from him through his descendants who used that name as well. So Chlorus is a.k.a. 'Eusebius I' and his son is 'Eusebius II', and so on. The information suggesting Emperor Constantine converted to Christianity cannot be trusted. Constantine "adopted" the Christian religion created by his ancestors as a tactical move to unite the many disparate Pagan tribes in the Roman Empire under just one belief system, leading to more unity right across the empire.
As mentioned earlier, "St. Jerome" translated the Biblical texts into Latin. "St. Jerome" was a descendant of Emperor Constantine, his name was Flavius Julius Eusebius of Rome (St. J(ulius) E(Eusebius) (of) Rome). His line of descent is below -