Diocletian (ruled 284-305) started administrative reforms in the empire to prevent the collapse of the empire. The reforms were continued by Constantine the Great (ruled 306-337).

The reforms were to mark a start of a new era which is nothing but an extension of the same Roman era but with different characteristics.
Constantine was very different than his predecessors. In 313 AD, he granted religious rights to all citizens to the empire, recognizing Christianity as on of the official religion of the empire. He gave back Christians their lost properties and allowed them to rebuild their churches.

Constantine the Great

Constantine founded Constantinople in 330. The establishment of the city would be later seen as an attempt to undermine Alexandria's distinctive role in the Mediterranean Sea and shift it to a new place.
Constantinople was founded on the remains of the old city of Byzantium. Henceforth, Constantinople would be made the capital of the Byzantine Empire until its fall in the 15th century by the hands of Ottomans. Constantinople is Turkey's present-day city of Istanbul.

The new Byzantine era would bear the characteristics of ideological differences among Christians.
Great patriarchs of Alexandria, Rome and Constantinople had to attend successive councils to discuss their differences and the evolving heresies.
Religious Alexandrian scholars showed a great talent dealing with heresies, particularly in councils that took place in Nicea 325 AD and Constantinople 381 AD.

A result of Constantinople's council was a decree considering Christianity as the sole religion of the empire. Councils took place again in Ephesus 431 and 449 AD. In 451 at Chalcedon, a new ecumenical council was held to overturn decisions reached in the last Ephesus council.

Coptic Art

A dispute erupted between the church of Alexandria and that of Constantinople. The Alexandrian church adopted a Monophysitism belief. Monophysitism is a belief that Christ has only one nature with both divine and human attributes in it.

The council of Chalcedon decided to validate the Dyophysitism belief. Dyophysitism is the belief that Christ has two natures, divine and human which are inseparably united.
The outcome of Chalcedon was sending Alexandria off on its own path to form the current Coptic Church. Dyophysitism is the belief of current Catholic Church.

The outcome of the split was terrible on Christianity. The gulf between the two tendencies widened after the council. Attempts to unite both faiths were undertaken by some Roman emperors but they all went to the wall.
Events went so fast. In Egypt people officially adopted the Coptic language instead of the Greek language in an endeavor to be distinctive.

Coptic Art

Things turned to be sort of struggle between the two faiths. After the council, the patriarchate of Alexandria was headed by two popes; one appointed by the Byzantine emperor, called a Chalcedonian pope and was usually rejected by Egyptians. The other pope, known as a Monophysite pope, was chosen by the people and rejected by the emperor.

Suddenly in 619 the Persians, Romans' old foes, conquered Egypt and occupied for 10 years. The period was nothing but a continued persecution of Egyptians. Thousands of monks were slain, others were severely tortured.
In 628, a peace treaty was forged between the Persians and the Byzantine Empire. This resulted in the Persians' withdrawal from Egypt.

After the liberation of Egypt, Emperor Heraclius (ruled 610-641) attempted to formulate a creed to unite the two faiths, blending Monophysitism and Dyophysitism in one faith; Monothelitism. Monothelitism is the belief that Christ has two distinct natures, divine and human, but with one will and activity. The new creed resulted into further division between the two faiths. Neither Monophysitism nor Dyophysitism approved the new creed.

Heraclius appointed one of his followers, Cyrus, a Chalcedonian, as patriarch of Alexandria to help spread his new belief. Cyrus was given both religious and civil powers which made him indeed very powerful.
Upon his arrival, Benjamin, the Monophysite patriarch of Alexandria, left to a small desert monastery. Adding insult to injury, Cyrus tried to carry his point by force. He started viciously to persecute Egyptians and as usual the people persisted in their faith.

The Coptic Language

Meanwhile, the Arabs' power was starting to rise in the Arabian Peninsula.
In 639, Arabs decided to conquer Egypt. So an army commanded by general Amr ibn El- Ãs marched to the Egyptian land. The troops took Egypt gradually until they reached Babylon fortress (present-day old Cairo) where a battle took place.

In 641, Byzantine Empire forged a treaty with Arabs surrendering Egypt and in 642 Amr ibn El- Ãs finally overtook Alexandria. Copts are said to have helped Arabs in their conquest, hoping to see a rule that is more tolerant. Fortunately the conquering Arabs didn't suppress Christians after invading Egypt.

Now a new era would begin. It would be very different than anything ever happened in Egypt.