The First Heaven

Hagia Sophia: the physical manifestation of the first heaven.

The first heaven is the universe of the Orthodox Church denoted by the five-pointed star of the famous Islamic star and crescent symbol. God in this universe is God the Father - the first person of the Blessed Trinity. The Father is number 7 (the seventh day when God rested from his work of creation and ruled over all his creations).

The five points in the five-pointed star are five wings of light representing the five patriarchates of the era of the Eastern Orthodox Church. The five patriarchates are:
  1. Ecumenical Patriarchate of Constantinople
  2. Holy See of Rome
  3. Patriarchate of Jerusalem
  4. Patriarchate of Antioch
  5. Patriarchate of Alexandria
The five patriarchates or five wings of light constitute the pentarchy whose identity is the ministry of John the Baptist. Since the pentarchy is about the five wings of light or the five pointed star, John is equal to 5.
The history of the Eastern Orthodox Church is traced back to Jesus Christ and the Apostles. The Apostles appointed successors, known as bishops, and they in turn appointed other bishops in a process known as Apostolic succession. Over time, five Patriarchates were established to organize the Christian world, and four of these ancient Patriarchates remain Orthodox today. - Wikipedia
Of the five patriarchates constituting John (5), only the Ecumenical Patriarchate of Constantinople attained the state of the Father; therefore the wing representing the Ecumenical Patriarchate of Constantinople is denoted by 7 (the Father). 

Each patriarchate in the pentarchy and its corresponding number in the five-pointed star is as follows:
  1. 7 = Ecumenical Patriarchate of Constantinople
  2. 2 = Holy See of Rome
  3. 3 = Patriarchate of Jerusalem
  4. 4 = Patriarchate of Antioch
  5. 5 = Patriarchate of Alexandria
God the Father resided in the Ecumenical Patriarchate of Constantinople, and Holy Wisdom flowed from there to other parts of Christendom in the era of the Orthodox Church. The Christian world looked up to the Church in Constantinople such that it was the first among equals in the first heaven. The first heaven was the first citadel, a university, of Divine Wisdom.

This means that the epicentre of the first heaven was located on earth in present day Turkey. Constantinople was the former name of present day Istanbul, and the fall of Constantinople was the destruction (the end) of the first heaven.

Hagia Sophia (Holy Wisdom or Divine Wisdom) was sunlight giving light to the whole world during the era of the Eastern Orthodox Church. The light was Christ shining forth from the Byzantine Christians to the whole world. Byzantine icons produced during this era are components of the light.

The first heaven is the layer of heaven directly above the world of the Jews such that the only knowledge of God at the disposal of the Jews was the knowledge of God the Father. The Jews couldn't comprehend the idea of God the Son because they were limited by the interval between the end (the destruction) of the first heaven and the beginning (the creation) of the second heaven. The second heaven is the abode of God the Son, built around the Holy See.

The first heaven is the pentagon, which was the military standard labarum of Emperor Constantine the Great. On the shield was the Chi Rho sign symbolising Christ.
The labarum (Greek: λάβαρον) was a vexillum (military standard) that displayed the "Chi-Rho" symbol ☧, a christogram formed from the first two Greek letters of the word "Christ" (Greek: ΧΡΙΣΤΟΣ, or Χριστός) — Chi (χ) and Rho (ρ). It was first used by the Roman emperor Constantine the Great. - Wikipedia