The Blue Mosque was built on the site of the old palace of the Byzantine emperors. Large parts of the southern side of the mosque rest on the foundation and vaults of the older palace. Several palaces had already been built there and first had to be bought at considerable cost and removed before the mosque construction could begin. According to Wikipedia, the design of the mosque is the culmination of 2 centuries of both Ottoman mosque and Byzantine church development. It incorporates some Byzantine elements of the neighboring Hagia Sophia with traditional Islamic architecture and is considered to be the last great mosque of the classical period. The architect aimed for overwhelming size, majesty and splendor.
A heavy iron chain hangs in the upper part of the court entrance on the western side. Only the sultan was allowed to enter the court of the mosque on horseback. The chain was put there, so that the sultan had to lower his head every time he entered the court in order not to get hit. This was done as a symbolic gesture, to ensure the humility (smallness) of the ruler in the face of the divine.
At its lower levels and at every pier the interior of the mosque is lined with more than 20,000 handmade ceramic tiles, made at ancient Nicaea. These tiles are in more than fifty different tulip designs. The tiles at lower levels are traditional in design, while at gallery level their design becomes flamboyant with representations of flowers, fruit and cypresses. The price to be paid for each tile was fixed by the sultan's decree, while tile prices in general increased over time. As a result, the quality of the tiles used in the building decreased gradually. Their colors have faded and changed (red turning into brown and green into blue and mottled whites) and the glazes have dulled. The tiles on the back balcony wall are recycled tiles from the harem in the nearby Topkapi Palace when it was damaged by fire in 1574. (Does anyone else besides me find this funny that tiles from a harem were used in the construction of a significant mosque!) The upper levels of the interior are dominated by blue paint. More than 200 stained glass windows with intricate designs admit natural light, which today are assisted by chandeliers. The prayer area of the mosque is lit by an enormous chandelier hanging from the ceiling. And I do mean enormous. This chandelier looks to be every bit of 50-feet wide. The floors are covered with carpets which are donated by faithful people and are regularly replaced as they wear out.
The interior of the huge dome is covered with blue tiles, which lends the common nickname of The Blue Mosque. The dome is supported by 4 enormous columns which are commonly called elephant pillars. Since this is an actively used mosque still today, everyone must remove their shoes prior to entry. Staff provide plastic bags to hold one's shoes as one approaches the entry. Women must have their head covered. Staff also have shawls for visiting women who do not have headscarves; but I cannot imagine putting on a headscarf that touched the hair of someone else. Head lice, anyone? I brought my own scarf; one that I had recently purchased in India for just this occasion; one that is large enough to be worn as a shawl if weather is a bit chilly. Cannot describe how stupid I felt standing barefoot inside a cold mosque wearing a big shawl wrapped around my head. But when in Rome.........