After a while Diocletian and the other Augustus became tired of reigning and resigned. Then, according to the original arrangement, Galerius and Constantius became Augusti. So far all worked smoothly; but Diocletian had decreed that Galerius should name the two Cęsars. It was expected that he would certainly name Constantine; but he was jealous of the young man's talents and popularity and did not name, him. Constantius was alarmed, for no one knew what might happen to his son. He sent letter after letter to Constantine to come to him in Gaul; but Galerius always had some trivial excuse for refusing to let him go. At length permission was given, but Constantine was wise enough to suspect that he would probably be prevented from going or would perhaps be waylaid and murdered after he had started, and, he traveled at full speed from Nicomedia to Dover Strait. There he met his father and was just in time to cross to Britain with him and the army.

The father and son succeeded in quieting the troublesome people of the north, and then returned south as far as York. There Constantius became ill and died. This was exactly what Galerius had been waiting for. He was sure that he could manage the two Cęsars, and with Constantius dead, there was nothing to hinder him from becoming ruler of the whole enormous empire. At least, he supposed there was nothing. He had not taken into account the fact that both father and son had been so just and kind to the soldiers that they were greatly loved by the army. The was no waiting for imperial edicts at York, and as soon as Constantius was dead, the soldiers who had been under his command put a purple robe upon his son and saluted him as Augustus.

Constantine sent a letter to Galerius, expressing his regret that there had been no chance to consult him and begging that he would confirm the choice of the army. Then Galerius Augustus was a very angry man. He declared that he would burn the letter and also its bearer; but he realized that it was not well to quarrel with the army, and at length he agreed that Constantine should have the title, not of Augustus, but of Cęsar. Constantine made no objection, but set off to govern Gaul.

Soon Galerius was in trouble. One Max-en'ti-us had expected to be made an Augustus; and when Galerius chose some one else, he took up arms. Then there was confusion indeed. At one time six men were all trying their best to win the sovereignty of the empire. After a while, Galerius died, and the number soon narrowed down to four. Maxentius was the most determined of these, and there was an appeal to arms by him and Constantine.

There is a famous legend that, when on an expedition against Maxentius, Constantine was one day praying to the sun god. Suddenly he saw in the sky above the sun a cross, and over it was written a Greek phrase meaning "In this sign thou shalt conquer." According to the legend, Constantine had a new banner made at once and displayed to his soldiers with the announcement that he had become a Christian. This banner was of purple silk and hung from the shorter arm of a cross. It was ablaze with jewels and showed images of himself and his children. At the top of the upright beam were the Greek letters which stand for the cross and also for the Ch-r  of "Christ." With this for his standard he fought with Maxentius the battle of Mil'vi-an Bridge and won a victory which gave him such power that he and Li-cin'i-us, one of his rivals, were able to divide the empire between them, Licinius taking the east and Constantine the west.

Both Constantine and his father had always been merciful to the Christians, and even when Galerius commanded that they should be persecuted, these two had never obeyed. The Christians were now treated with fairness. The laws against them were repealed and their churches and other property which had been seized were given back. The Christians had felt that they ought to be a people of peace, and they had shunned warfare; but now when Constantine's army went into battle, it followed the sign of the cross. That made the matter look entirely different, and great numbers of them joined his troops. He had need of them, for there was soon a war with Licinius; and when it had come to an end, the whole empire was in the hands of Constantine.

Constantine decided to choose a new capital. He thought of taking the old site of Troy; but finally he decided upon By-zan'ti-um on the Bos'pho-rus. He changed its name to Con-stan-ti-no'ple, or city of Constantine. It was an excellent location for trade, and it was near the most troublesome enemies of the Romans, that is, the Persians and the people north of the Dan'ube. Everything possible was done to make the new city handsome. Splendid houses and public buildings were raised; churches, palaces, theatres, baths, and circus were all built. The greatest artists of the time were employed, and Constantine even took from the cities of Greece and Asia Minor statues and ornaments, anything that could be carried away, to beautify Constantinople.

Constantine had worked hard to get the supreme power, and he had no idea of giving up any of it. He made a great many generals, but gave each one so few soldiers that there was little chance of any rebellion against himself, and he also divided the provinces into small districts, each with its governor. Every man who was in office was anxious to prevent any rebellion, for that would throw him out; and therefore this large body of governors and generals and magistrates was a mighty guard to keep the empire strong.

The empire was strong, but just beyond its limits were Goths, who were ever trying to break into its circle. Emperors who were powerful thrust them back. Emperors who were weak had to yield and let some of the Goths settle within the Roman bounds. So it went on for three quarters of a century. Then came Al'a-ric, a Gothic leader who Rome could not drive away.

Diocletian's brilliant idea. — Constantine goes to Britain. — He is saluted as Augustus, but becomes Cęsar. — Confusion in Rome. — The vision of Constantine. — The Christians join his army. — He becomes sole ruler. — The new capital. — Constantine's plan of government. — The Goths.