Domes was not an Islamic invention – the Muslim architects only start to use the architectural feature in the 7th Century, taking influences from the Sassanid Empire in Iran and from the Byzantine Empire.
The first ever building that the Muslims built with a prominent dome is the famed Dome of the Rock on the Temple Mount in Jerusalem, Palestine, which is incidentally the oldest existing Islamic building without any alteration. Completed around 691-692, the building, a hexagonal shaped shrine is built over a stone believed to be the stepping stone of Prophet Muhammad during his journey heavenwards to God. It is also, as a notable feature, decorated with tiles that brought over from Turkey – Iznik tiles- all over its exterior walls. The shape of the whole building displays influences of Byzantium architecture, echoing the form of a Byzantine martyrium (which is traditionally used for keeping venerated saintly artifacts and relics). On top of the building built a dome made out of wood and covered with gold ; it is said that 100,000 gold dinars were melted for the covering of the dome, and when it was finished, it was reported at that time that “no eye can look straight to it” due to its strong shine.
The Dome of the Rock, with its golden dome in the vicinity.
As noted before the Dome of the Rock’s plan and architecture is much influenced by Byzantium architecture, mostly by the surrounding churches. In addition to the similarity of the floorplan of the shrine to Byzantine martyrium, the dome also influenced by domes of the churches of the Byzantine empire.
In 532AD, The church Hagia Sophia, or Aya Sofya (Ἁγία Σοφία) in Greek was completed and is in its third and final form, after the destruction of the first and second churches. An entirely different structure compared to its predecessors, emperor Justinian I wanted a building much larger and more majestic than what was built on the same site nearly 200 years before. He appointed Isidore of Miletus and Anthemius of Tralles as architects, and these two created one of the most recognized work of Byzantium architecture, which features a grand and imposing dome in the middle of the church. It is thought that they utilized the theories of Heron of Alexandria regarding of construction of large domes over large open spaces.
The Hagia Sophia, once a church, a mosque and now a museum.
Nearer to the Dome of the Rock, another influence of the dome is the Church of Holy Sepulchre. The dome of the church itself is very reminiscent of the dome that decorated the Muslim shrine, though lacking the golden entrapment. The Church itself was built in the 4th Century under the orders of Emperor Constantine I over the alleged tomb of Christ and also Mount Golgotha, the site where Christ were crucified. Perhaps, as an act of mockery against Christianity’s deification of Christ, the Muslim architects followed the model of the Churches dome for the Dome of the Rock, only larger and more impressive, as in using gold for covering the dome. This idea is supported with the fact that the Muslims used Quranic verses for decorating the exterior and interior of the shrine that stated Christ was not the Son of God, he was a mere human, and a prophet of God.
The Church of the Holy Sepulchre, the front facade.
Using the theories of Heron of Alexandria that have been executed by the two architects of Justinian I, Isidore of Miletus and Anthemius of Tralles, coupled with the apparent influence from the domes of the Church of the Holy Sepulchre, the Muslims created an architectural feature that which in time will transform and metamorphose into a unique feature. At first they were influenced and followed the domes of other cultures, but as time went they created features that makes the domes more Islamic.