By the 3rd or 4th Century, Rome had expanded to a vast empire, which was beset by enemies around it. The early Roman emperors were not like modern British kings and queens, inheriting the throne from their fathers; they were generals who had the command of the armies and as a result could protect Rome from its enemies. The emperor's first and foremost task was to protect the Empire and keep the peace, either by commanding his generals or by leading the army himself.
There was no requirement that the emperor should be from the city of Rome itself. The Emperor Diocletian was from Illyrica, which is now Croatia; having served much of his working life as a soldier at the frontiers of the Empire, he had no great ties to Rome. When he became emperor, he decided to move to Nicomedia, which is now Izmit in Turkey1. The Senate and all the rest of the trappings of government remained in Rome. This was just a temporary move, in that Diocletian was the only emperor who ruled from Nicomedia, but it set the scene for the move to Constantinople.
The Rise of Constantine to Emperor
Diocletian wanted nothing more than to retire to his estate and grow cabbages, so he devised a bureaucratic system of appointing emperors which treated the position of ruler of the known world like any other job. He divided the Empire into two, East and West, and gave the rule of the West to his friend Maximian. Then he came up with a system of appointing successors. Unfortunately, he reckoned without the ambition of others, and forgot that people would fight to be Emperor.
Constantine was born in about 274 AD in Naissos (now Nis) in Serbia. His father was Constantius, a general in the army; his mother was Helena. When Diocletian split the Empire, Constantius was appointed Caesar (Junior Emperor), which meant that he would inherit the title of Emperor of the West when Maximian died or stepped down.
In 305, Diocletian and Maximian abdicated, and the squabbling started - Galerius and Constantius became Emperors of the East and West respectively, but there were arguments about who should succeed them. Constantius died soon afterwards in 306, and by the time of Galerius's death in 311, there was all-out civil war.
Battling for control of the West were Constantine (son of Constantius and son-in-law of Maximian) and Maxentius (son of Maximian and son-in-law of Galerius). Constantine controlled Gaul and England, while Maxentius held Italy. Constantine's armies advanced through Italy and finally met up with Maxentius's army at the Battle of the Milvian Bridge just outside Rome. Constantine was victorious and Maxentius's army sought to retreat across the narrow bridge across the Tiber. Many were killed in the crush, including Maxentius himself. Constantine was now sole ruler of the West. Meanwhile in the East, a general called Licinius had emerged as victor and Emperor of the East.
This should have settled things, but Constantine was more ambitious than that. He wanted to rule the entire Empire. He attacked Licinius in 314 but failed to make any progress. Nine years of peace followed, then he attacked again in 323. This time, he was successful and became sole ruler of the Empire.
Christianity: The Vision
Legend has it that during his war against Maxentius, just before the Battle of the Milvian Bridge, Constantine had a dream - he saw a giant cross in the sky inscribed with the words 'Hoc Vince' ('in this sign, conquer'). Recognising the cross as the symbol of Christianity, he ordered all this troops to paint a cross onto their shields. They won the battle, and Constantine was converted to being a Christian.
There are some problems with the traditional dream story. It's not clear what symbol was drawn on the shields - in some versions, it is the Christian 'chi-rho' symbol rather than a cross. This is made from the first two letters in Greek of Christ's name, and looks to us like a P and an X superimposed. In either case, such an action would surely have been recorded by historians at the time, but there is no mention of it. It sounds suspiciously like a miracle invented after the event.
In any case, Constantine declared Christianity to be the official state religion of the Western Roman Empire, and later when he conquered the East, it became the official religion there too. While people were free to worship any gods they liked, the state now favoured the Christians, provided churches for them, and modified many laws to fit in with the new religion. Christianity remained the religion of the people for the entire history of Byzantium, although one later emperor, Julian, tried unsuccessfully to re-instate the old pagan gods.
The Council of Nicaea and the Nicene Creed
Having settled the issue of a state religion, Constantine was determined that there should be one version of this religion, and that everybody should follow one set of rules. He organised the First Ecumenical Council at Nicaea (now Iznik, Turkey), calling eminent Christians from all over the Empire. These debated the theological matters (in Greek, which Constantine could not understand) and eventually came up with the 'Nicene Creed', a statement of belief which defined Christianity. This Creed is still recited by Christians all over the world, virtually unchanged, to affirm their beliefs.
The New City
Constantine decided to move the capital of the Empire lock, stock and barrel to a new city. This was not so much to abandon Rome but more to secure the East. Without a guard on the Bosphorus (the narrow strait which separates Europe from Asia), barbarians could sail down from the Black Sea and invade all parts of the Eastern Empire. There was also a threat from Persia. With the Bosphorus secured, the whole of the Eastern Empire was stabilised.
The East was also the richest part of the Empire - Egypt at the time produced most of the food for the Empire, and trade with Persia brought in many exotic and expensive goods such as silks and spices. Building a new city from scratch gave him the opportunity to set it all up the way he wanted it, rather than inheriting archaic traditions that came with the existing city of Rome.
Rather than returning to Nicomedia, Constantine chose the city of Byzantium. This was a small Greek city, on a hill overlooking the Bosphorus, which could be easily defended. Byzantium had been founded in the 7th Century BC as a Greek colony by the people of Megara near Athens, and had been reasonably successful until it was subsumed into the Roman Empire.
The original Byzantium was located on the present site of the Topkapi Palace in Istanbul. It is worth describing the position of the seas around here, as they can be confusing:
There is a strip of land about 35km wide between the Black Sea to the north and the Sea of Marmara to the south. Byzantium was on the south side of this land, on the Sea of Marmara. Joining the Black Sea and the Sea of Marmara is a narrow strait called the Bosphorus or Bosporus. It runs roughly southwest to northeast and forms the border between Europe and Asia. It is only 700m wide at its narrowest point. On the west side of the Bosphorus is an inlet about seven kilometres long called the Golden Horn. The name is supposedly derived from the fact it is in the shape of an ox's horn and the water turns gold at sunset. The Sea of Marmara, the Bosphorus and the Golden Horn are known as the 'Three Seas'.
To the south of the Golden Horn, at the tip of the triangular peninsula between it and the Sea of Marmara, stood the city of Byzantium. It was surrounded on three sides by water, with the Golden Horn to the north, the Bosphorus to the east and the Sea of Marmara to the south. To the west of the city was the farmland where the residents grew their crops.
Constantine chose this area for his new city. Leaving the old city more or less alone, he marked a spot just to the west as the centre of the New City. A monument called the Milion was built on this spot, and it marked the point from which all distances in the Empire were to be measured.
The Walls of Constantine
The new city was founded on Monday, 11 May, 330 AD. Legend has it that Constantine marched west from the Milion through the fields, eventually stopping when he reckoned he had marked out enough space for his city. This marked the west end of the new city; a set of defensive walls were built here, running north/south and joining the Golden Horn to the Sea of Marmara. The walls were known as the Walls of Constantine. These walls didn't last long - only a few hundred years. The city very quickly overflowed them and much bigger walls had to be built further out - the second set of walls, known as the Walls of Theodosius, are still standing. The original walls of Constantine were then removed.
The entire sea coast around the new city was then fortified with sea walls, so that the whole city was easily defended.
Within the space marked out by the walls, Constantine ordered the building of a palace (just to the south of the Milion), a Senate House, a new Forum (a meeting square), many churches, the most important ones being Hagia Sophia - the Church of Holy Wisdom (the original, not the present building) - and the Church of the Holy Apostles, which is no longer in existence - its site is now occupied by the Fatih Mosque. There were also giant cisterns built to hold drinking water which was brought by aqueducts from the hills to the west. For the amusement of the people there were theatres, public baths, and the existing horse-racing track, the Hippodrome, was refurbished.
The Forum of Constantine
The Forum of Constantine still stands in Istanbul, where it is now known as Çemberlitas. It was originally elliptical in shape, with a triumphal arch at each end, lines of pillars down each side, and statues of gods and goddesses standing between the pillars. It may seem odd that a Christian emperor should erect statues of gods, but there was a good reason. The statues were plundered from pagan temples around the Empire. This meant they could no longer be adored in their temples, but provided a cheap method of quickly adding a bit of class to the new city.
In the centre of the Forum he built a giant column - this was 120 feet high in total, with 100 feet of cylindrical column, 10 feet in diameter, standing on a square base 20 feet high. On top was a bronze statue of Apollo pilfered from one of the Greek temples, carrying a sceptre in one hand and the world in the other hand. The head of Apollo was removed and replaced with a head of Constantine himself, ruling the (known) world. The column is still standing, now known as the 'burnt column', although the statue is gone. At some point in its history, bands of metal were added to strengthen it, making it look very ugly, but originally it would have been an elegant structure.
Byzantium already had a small horse-racing circuit known as the Hippodrome ('hippo' in Greek means 'horse'). Constantine had this completely rebuilt, making an impressive building which became the cultural centre of the city. It was in the shape of a long narrow rectangle with one end rounded. All around the outside of the race-track were tiered seats, which could hold about 100,000 people. Down the centre of the track was a raised 'spine'. On this Constantine placed statues and monuments which he brought to the city from various places around the Empire. One such was the Tripod of Plataea, a strange bronze monument with three snakes twisted to make a single pillar. This was supposedly made from the shields of the defeated Persians at the Battle of Plataea, and offered to the Oracle at Delphi. It was brought to Constantinople and put on display to show that Constantine was greater than the old pagan gods.
The Hippodrome was connected directly to the Great Palace, so that the emperor could easily attend the games, and leave when he wanted to.
The Hippodrome itself is no longer in existence, but the site was never built upon and this long narrow space is now known as Sultanahmet Square. Later emperors added to the monuments in the centre of the Hippodrome - Theodosius brought a huge obelisk from Luxor, Egypt, and Constantine Porphyrogenitus matched it with another obelisk at the other end. These obelisks can still be seen in the square. Part of the Tripod of Plataea, now known as the Serpentine Column, is still visible as well, although the ground level has risen in the intervening 17 centuries, so it is down in a hole. The snake heads were broken off it about 300 years ago by a drunken Polish officer; one of them is still visible in the Istanbul Archaeology Museum.
The Filling Up of the City
The new city was intended to take over all the administrative functions that had previously been carried out in Rome. There was a new Senate and a new Emperor's palace. Many Romans took up the offer of better jobs and bigger estates around the new city. But Rome was not left empty. The old Roman Senate continued to operate, and the really rich Roman families would have stayed behind in their city, gradually becoming forgotten about.
Constantine's mother, Helena, was a humble woman - the daughter of an inn-keeper, she married a man who became Emperor. He had later deserted her to marry a better match, but her son Constantine never abandoned her. When he himself became Emperor, he summoned her to the court and declared her as Empress. It is said that after Constantine's God-inspired defeat of Maxentius, Helena was converted and became a devout Christian.
When she was about 80, she became the first Christian pilgrim and made a trip to Palestine to see the places where Christ had lived and died. Her trip was a resounding success. She brought back to Constantinople a whole series of objects which everyone agreed were genuine holy relics - the most important of these was the 'True Cross' - the cross on which Jesus Christ was crucified. One legend is that Constantine later incorporated the nails from this cross, the nails with which Jesus had been killed, in the statue of himself on the column in the Forum of Constantine, thereby providing divine protection for the entire city. According to another story, one of the nails was used for Constantine's horse's bridle, another for Constantine's helmet and two more were thrown into the Adriatic Sea to bring divine protection.
The Death of Constantine
Throughout his life, Constantine supported Christianity, yet he never officially became a Christian himself, until his final moments. On his death-bed, he was baptised into the faith and finally became the first Christian Emperor.
Constantine died on 22 May, 337, and at his command his body was placed in a sarcophagus in the Church of the Holy Apostles, with 12 other sarcophaguses, representing the 12 Apostles, around him. He obviously considered himself to be the 13th Apostle. He left behind him a strong Empire with a spanking new capital city and a brand new religion. He is known in the history books as Constantine the Great.
1 This town is right on the North Anatolian Fault, and suffered a catastrophic earthquake of magnitude 7.4 in 1999, killing more than 17,000 people.