Constantine I (Latin: Constantinus I Magnus, February 27, 272 or 274 [1] - May 22, 337), whose full name is Gaius Flavius Valerius Constantinus (Latin: Gaius Flavius Valerius Constantinus), Augustus of the Roman Empire (i.e. the emperor, reigned from 306 to 337), and the eldest son of Constantius I of Augustus in the western Roman Empire [2].
In his early years, Constantine was sent to the Eastern Empire to serve Augustus Deckery first and then to fight in Britain. In 306, it was established as Augustus. Later, it won a series of civil wars against Maxentius and Licinius, and reunited the Roman Empire in 324. During Constantine's reign, he carried out a series of reforms: politically, he reorganized the government and separated the civil and military authorities; Economically, in order to fight against inflation, the introduction of solid money; Militarily, the roman army was reorganized to repel the attacks of the franks and goths; In terms of religion, he first issued the "Milan edict" with Licini, and then held the Nicene Conference in 325 to vigorously promote Christianity. In 330, Constantine moved his capital to Byzantium, renamed New Rome, and became the capital of Constantinople. In 337, Constantine died in Nicomedia and was baptized as a Christian before his death. [3] After his death, he was buried in the St. Apostle's Church in Constantinople. [9]
Constantine not only granted Christianity legal status and many privileges, but also forcibly adopted the belief of "trinity" as the orthodox doctrine, which actually made Christianity obtain the status of national religion. [16] He was the first monarch from Rome to Christianity, and was honored as Constantine Magnus.

Early experience
Constantine Head Carving
In 272 or 274 [14] (and 273 [16] and 282 [2]), Constantine was born in Nessus, the province of Mercia in the Roman Empire (now Nish in eastern Serbia) [14]. [4] His full name is Gaius Flavius Valerius Constantinus (Latin: Gaius Flavius Valerius Constantinus). He is the eldest son of Constantius I Kroll, the western Augustus of the empire (the emperor [8], see the entry "Four Emperors rule together"). He is related by blood to Augustus Claudius II at the end of the third century. [16]
It is said that Helena, Constantine's mother, was a maid in a small inn, and Constantine was her illegitimate son with Constantius. However, this statement was doubted by the British historian Edward Gibbon. Gibbon believed that Helena was the owner of the inn and that her marriage to Constantius was legal. Anyway, when Constantius was appointed Caesar by Maximian, the Augustus of the Western Empire, in 293, he left Helena and married Theodora, the daughter of Maximian.
Constantine had followed his father in the battle since he was young, and he developed a strong will and a strong physique. After Constantius became Caesar, he was once held as a hostage under the leadership of Diocletian Augustus of the Eastern Empire and became a civil servant in Diocletian's court. [16] In 302, he served as a military civilian protection officer in the Eastern Empire. [2]
In 305, Diocletian and Maximian both abdicated. The successor of Diocletian, the eastern Augustus Galerius, was more suspicious of the new western Augustus Constantius and tried to prevent Constantine from returning to his father. [16] Later, Constantine took the opportunity to escape from the east and went to Britain to meet his father and fight with barbarians in Britain. [

The fight for the throne
On July 25, 306, Constantius died. On the same day, the British Legion declared Constantine Augustus in Iborakum, Britain (now York, England). But Galerius gave him only the title of Caesar. [3] At this time, after the death of Constantius, Licinius, who was appointed by Galerius to succeed him, Maxentius, the son of Maximian, who was supported by some armies, Severus and Daza (Daya), who had been appointed as the two Caesars by Galerius, and Maximian, who had abdicated, together with Constantine, launched a fierce power struggle for the position of Augustus. [5]
In October 306, Maxentius usurped the throne and Constantine expressed his support. In 307, Severus, who was stationed in Milan, was killed due to military mutiny. In 310, Maximian launched a rebellion while Constantine was away, and was besieged by Constantine's army in Marseilles and forced to commit suicide.
Milvian Bridge Campaign
Milvian Bridge Battle [17]
In 311, Galerius died of illness, and Constantine began to unite Licinius against Maxentius. [3] He crossed the Alps, defeated Marcentius's army in the Battle of Turin, and occupied Italy. [9]
On October 28, 312, Constantine defeated Maxentius in a decisive battle near the Milvian Bridge on the Tiber River (see the term Milvian Bridge Battle). Maxentius fell into the water and died in his escape. Constantine put the Maxentius family and important followers to death to get rid of future troubles. Then he entered Rome as a winner.

Unified empire
Head sculpture of Constantine the Great
In 313, Constantine met Licinius in Medioran (now Milan, Italy) and agreed to implement a tolerant policy towards Christians. Licinius agreed. Licinius married Constantia, Constantine's sister, to consolidate their alliance. At the same time, the two Augustes issued the "Milan statement" (see the Milan edict). Christians and people with other religious beliefs have the right to freely choose their beliefs, and all measures against Christians have been declared invalid. [5] Its background is based on political intentions, and it wants to win the support of the majority of Christians and supervise the defense of the Euphrates River.
After the meeting, Licinius led his army to the east to fight against Daya (Gaius Valerius Galerius Maximinus), who was an Augustus, and defeated him completely in the Battle of Tezralum in 315. So Licinius in the east, Constantine in the west, and the situation of two Augustus standing side by side resumed. Constantine was unwilling to follow the pattern of coexistence of two males and expand his power. Licini was worried about this, so he violated the agreement at the Milan meeting and began to persecute Christians in his jurisdiction. [5]
In the final struggle to complete the great cause of reunification, Constantine fully demonstrated the strategies and talents of a politician. He strengthened the control of the army, improved the military construction, carried out the policy of religious tolerance in the regions under his rule, and greatly strengthened his own strength. [18]
The image of Constantine in the mosaic mosaic of St. Sophia Cathedral
The image of Constantine in the mosaic mosaic of St. Sophia Cathedral [9]
Constantine took the opportunity to attack Licinius. In 316, Constantine captured Licinius' territory in the Balkans. In 323, he attacked Thrace, the eastern empire. On July 3, the 170000 troops of Licinia were defeated at the Battle of Adria Fort to hide in the wall of Byzantium. Later, Licini's fleet was destroyed in the Battle of the Hellespont Strait. He had to leave the newly promoted Caesar Martinianus to continue to defend, and he retreated to Crespolis. He was defeated again in the decisive battle on September 18. Finally, he fled to Nicomedia, his hometown, and surrendered under the guarantee of saving his life. However, Constantine hanged Licinie in 325 in the name of conspiracy, treason and adultery with barbarians. Since then, Constantine has become the only ruler of the Roman world, namely Constantine I. [5] [2]
On May 20, 325, Constantine ordered Joseph of Nicosia to fight against the pagans. [2]
In 326, Constantine visited the west and arrived in Rome to celebrate. However, his visit to Rome was unsuccessful because he refused to participate in the pagan parade, which offended the Roman people. This was the last time Constantine arrived in Rome in his lifetime. [
On May 11, 330, Constantine moved the capital of the Roman Empire from Rome to Byzantium, and named the city New Rome. However, it was generally called Constantinople in the name of its founder. [3]
Between 332 and 334, Constantine helped the Salmates resist the Goths and commanded the battle himself. [2]

Establishment and death
In order to maintain the continuity of the dynasty, Constantine determined his eldest son, Crispus, and his second son, Constantine II, as the successors of the emperor on March 1, 317, and appointed them as Caesars. However, Chris Puss, whom he placed high hopes on, had outstanding military achievements and superior abilities, was suddenly executed in 326 because he was suspected of having an affair with his stepmother Fausta, who was close to his age, or because he was suspected of a major crime that could not be verified [19]. This matter had a great impact on Constantine I. In order to ensure the continuous rule of the dynasty, he first appointed the third son Constantius II as Caesar in 324, and then appointed the fourth son Constantine I as Caesar in 333. Thus, in the later years of his rule, his three sons were determined to be the successors to the throne. [18]
Later, Constantine fell ill while preparing for the battle against Persia and was forced to return to Constantinople. In order to prevent conflicts over imperial power between several brothers after his death, Constantine divided their spheres of influence for the sons, that is, Constantine II controlled Britain, Gaul and Spain, Constantius II controlled Thrace, West Asia and Haiti, and Constans controlled Italy, Africa, Dagia and Macedonia. [4] [18]
On May 22, 337, Constantine died in the palace of Ancelona in Nicomedia. On his deathbed, he was baptized as a Christian. After his death, he was buried in the royal cemetery of St. Apostle's Cathedral in Constantinople.