Constantine`s reign set a precedent for the position of emperor, which had great influence and ultimate regulatory authority in the religious discussions of the early Christian councils of the time (especially the dispute over Arianism and the nature of God). Constantine himself did not like the risks to social stability that religious conflicts and controversies entailed, preferring to establish orthodoxy whenever possible. One way Constantine used his influence on early church councils was to build consensus on the often debated and controversial question of the nature of God. In 325 he convened the Council of Nicaea, practically the first ecumenical council. The Council of Nicaea is best known for its confrontation with Arianism and for the introduction of the Nicene Creed, which is still used by Christians today. After Constantine, only a few emperors ruled over the entire Roman Empire. It was too big and was attacked from too many directions. Normally, an emperor of the Western Roman Empire ruled from Italy or Gaul, and an emperor of the Eastern Roman Empire ruled from Constantinople. While the Western Empire was invaded by the Germanic barbarians (its lands in Italy were conquered by the Ostrogoths, Spain was conquered by the Visigoths, North Africa was conquered by the Vandals, and Gaul was conquered by the Franks), the Eastern Empire flourished. Constantinople became the largest city of the empire and an important commercial center. In 476 AD, the last Western Roman Emperor was deposed and the Western Roman Empire no longer existed. Thus, the Eastern Roman Empire was the only Roman Empire that remained.
In the Middle Ages, the British regarded Constantine as the king of their own people and associated him in particular with Caernarfon in Gwynedd. Although this is partly due to his fame and proclamation as emperor in Britain, there has also been confusion between his family and Magnus Maximus` presumed wife, Elen, and their son, another Constantine (Welsh: Custennin). In the 12th century, Henry of Huntingdon included a passage in his Historia Anglorum that the mother of Emperor Constantine was British, making her the daughter of King Cole of Colchester.  Geoffrey of Monmouth developed this story in his Historia Regum Britanniae, a highly fictionalized account of the alleged kings of Britain from their Trojan origins to the Anglo-Saxon invasion.  According to Geoffrey, Cole was King of the British when Constance, here a senator, came to Britain. Fearing the Romans, Cole submitted to Roman law as long as he retained his kingship. However, he died only a month later, and Constance himself ascended the throne and married Cole`s daughter, Helena. They had their son Constantine, who succeeded his father as King of Great Britain before becoming Roman Emperor. During the 4th century, the Christian body was consumed by debates about orthodoxy, that is, which religious teachings are the right ones. In the early 4th century, a group in North Africa, later called Donatists, who believed in a very rigid interpretation of Christianity that excluded many of those who had abandoned the faith during Diocletian`s persecutions, caused a crisis in the Western Empire.  An ecclesiastical synod or council was convened in Rome in 313, followed by another in Arles in 314.
The latter was ruled by Constantine while he was still a young emperor. The councils decided that the Donatist faith was heresy, and when the Donatists refused to recant, Constantine launched the first campaign of persecution by Christians against Christians. This was only the beginning of imperial engagement in Christian theology. In the 3rd century, the production of fiat money to cover public spending led to runaway inflation, and Diocletian tried unsuccessfully to restore the reliable minting of silver and billon coins. Silver money was overvalued in terms of actual metal content and could therefore only circulate at very low rates. Constantine stopped minting Diocletian`s « pure » silver silver shortly after 305, while billon money was used until the 360s. Beginning in the early 300s, Constantine abandoned any attempt to restore silver coinage and instead focused on minting large amounts of gold solidus, 72 of which yielded a pound of gold. New heavily devalued silver coins were issued during his later reign and after his death in a continuous process of re-pricing, until this minting of gold was interrupted in 367 and the silver coin was continued by various denominations of bronze coins, the most important of which was the Centenionalis.
 These bronze coins continued to be devalued, allowing the fiat minting to be kept next to a gold standard. The author of De Rebus Bellicis believed that the class gap had widened as a result of this monetary policy; The rich have benefited from the stable purchasing power of the gold coin, while the poor have had to deal with ever-deteriorating bronze coins.  Later emperors such as Julian the Apostate insisted that bronze coins be minted reliably. After his rise to the rank of emperor, Constantine promulgated numerous reforms to strengthen the empire. He restructured the government and separated the civil and military authorities. To combat inflation, he introduced the solidus, a new gold coin that became the standard for Byzantine and European coins for over a thousand years. The Roman army was reorganized into mobile units (comitatenses) and garrison troops (limitanei) capable of countering internal threats and barbarian invasions. Constantine led successful campaigns against tribes on the Roman borders – such as the Franks, Alemanni, Goths and Sarmatians – and populated the territories abandoned by his predecessors during the crisis of the third century with citizens of Roman culture. Constantine I`s father became Western Roman Emperor in 305. After his father`s death, Constantine fought for power. He became emperor of the West in 312 and sole Roman emperor in 324. Constantine was also the first emperor to join Christianity.
He issued an edict protecting the Christians of the empire and converted to Christianity on his deathbed in 337. Emperor Constantine (ca. 280 – 337 AD) ruled over a great transition in the Roman Empire – and much more. His adoption of Christianity and the founding of an eastern capital, which would later bear his name, marked his reign as an important turning point between ancient history and the Middle Ages. « Without warning, purulent inflammation broke out in the middle of his genitals, and then a deep fistula ulcer; These ate incurably in his deepest intestines.