Sultanahmet Cami - Kilim and Carpet Museum - Aya Sofia

Sultanahmet Cami, known to the west as the Blue Mosque, stands next to the ancient hippodrome on the site of the Byzantine palace. It was built in 1609-17 by the architect Mehmet Aga, and was the last and largest of the imperial mosques to be built during the Ottoman era. It is one of the few mosques in the world with 6 minarets, and it has a 22.5m (74ft) diameter dome that nearly equals that of Aya Sofia in size. The dome, which is 43m (141ft) high, is supported by four large fluted columns each measuring 5m (16ft) across.

The main entrance is reached through a spacious courtyard surrounded by granite columns with a hexagonal wrought-iron ablutions fountain at the centre. Visitors, however, should use the side entrance and keep within the partitioned area so as not to disturb worshippers. Head-scarfs and coverings are issued at the door.

Inside, the hall measures 72m (236ft) by 64m (21 Oft) and is well lit by 260 small windows set into the walls. The walls are clad with over 21,000 blue-coloured tiles which were made in İznik and give the mosque its name. The best tiles are set in panels along the galleries on the first floor. The mimber is carved from white Marmara marble and the prayer niche contains a piece of the black kaaba stone from Mecca. The sultan's royal box, originally entered by horseback, is to the left. Ahmet I, who commissioned the mosque, died just 6 months after the building was completed at the age of 28 and his tomb is attached to one side. The mausoleum also contains his brothers and two other sultans, Osman II (1622) and Murat IV (1640).

The Kilim and Carpet Museum is housed in the imperial suite of rooms joined to the north corner of the mosque, known as the Hunkar Kasri, where the sultan formerly rested before and after praying. A Son et Lumiere outlining the history of the mosque is held free of charge, in four languages, on alternate evenings, in front of the mosque during the summer season.

The solid brick-red walls of Aya Sofia look somewhat clumsy next to the elegant contours of Sultanahmet Cami, but the broad but tresses and outer walls were never part of the original design. They were added later to support the dome, the fifth largest in the world, with a diameter measuring 31-3m (1 01-8ft), which has collapsed on more than one occasion.

The earliest basilica on the site was made of wood and was built in AD360. It burnt down but was rebuilt by Theodosius ii in 415, and destroyed again in 532 during the Nika revolts. The basilica seen today was founded by Justinian, just 9 days after the revolts; construction work started in 532 and the basilica was officially opened in 537. It was designed by the well known architects Isidoros of Miletos and Anthemios of Tralles, and the very finest materials were used in its construction: yellow marble from North Africa, red porphyry and granite from Egypt, green columns from the Artemis Temple at Epheseus, local marble from the island of Marmara, as well as light bricks made in Rhodes for the dome. The inner surfaces were coated with mosaics and gilded with gold, but were badly destroyed in the iconoclastic movements of 726-842.

In 1453 Mehmet II officially converted the basilica to a mosque and added a medrese (a religious school) and a minaret. His son Beyazit added another minaret and Murat III built the last two. In the eighteenth century the mosaics were plastered over and four large piers were built onto the exterior to support the dome. Mahmut I added a library, an other school and an ablutions fountain, and converted the baptistry to a mausoleum for Mustafa i and his son Ibrahim. At the end of the Ottoman empire there was great dispute as to whether the republic would recognise Aya Sofia as a church or a mosque. The matter was settled in 1935 when it was opened as a museum.

A ninth-century bronze door on the west side leads into the narthex, a large hallway with nine doors gaining entrance to the 9, basilica. The largest door, used for royal ceremonial processions, has a ninth century mosaic in the lunette above showing the Emperor Leo Vi kneeling before Christ. The main hall measures 77m (252ft) by 72m (236ft) and the highest point of the dome, which gives the impression of floating above the forty windows that surround its base, is 55m (180ft) above the floor. of the four great columns supporting the dome the one to the left nearest the door is known as the sweating column of St Gregory. An indentation has been worn in the marble by generations of people placing their fingers into the cavity for good luck; if a damp, 'sweaty' sensation is felt, wishes are meant to come true.

A circular mosaic in the floor of the hall marks the place where Byzantine emperors were crowned in the eighth and ninth centuries, and some of the column capitals bear the monograms of Justinian and Theodora, but the best remaining Byzantine decorations are the mosaics in the upper galleries. The four Islamic cartouches hanging in the main hall were added in the seventeenth century and the alabaster vessels, from ancient pergamum, were also brought to the mosque during the Ottoman period.

A winding ramp leads from the north end of the narthex to the galleries. The south gallery was used by the emperor and his family and contains impressive mosaics dating from the eleventh and twelfth centuries. Only the upper section remains of the Deisis, a magnificent mosaic depicting Christ with the Virgin Mary and John the Baptist, but there are two well preserved smaller mosaics at the east end of the south gallery.