The Royal Doors
The frame is of bronze and dates from the sixth century. The cornice is ornamented with crosses. There are many bronze hooks in the shape of fingers to hold curtains on the cornice. The mosaic above shows Emperor Leo the Wise before an enthroned Christ.
Here you can see a bronze arch with a cross and inscription.
The original doors where covered in silver with a huge silver lock. The doors were opened on special days and only the Emperor could enter through them. It and it was claimed they had been made of wood from Noah's Ark. The threshold is a huge slab of dark Verd Antique marble. The light gray marble in front of the door is badly worn. There were famous icons on either side of the door; on the left was one of the Chalke Savior, it was believed you could pray before this icon and have your sins forgiven. One the right side was a famous icon of the Theotokos from Jerusalem with another one of St. Mary of Egypt. When the doors were shut this area was used like devotional shrine. Every pilgrim would have venerated the ikons here before entering the church. They were hung about six feet above the floor and the hooks are still there. You can actually see where hundreds of thousands knelt beneath them, there are deep depressions in the marble left by their knees. The icons were covered in gold, silver and jewels.
The Byzantines were famous for the silver and bronze doors they made for their churches. Enormous amounts of silver were applied to the the doors of the most important shrines. Emperors were tempted to remove the the silver from church doors in times of financial trouble and Alexios I actually did it during the darkest days of his reign. Hagia Sophia would have been immune from this to a great extent. The church was too important and was visited by thousands everyday. Removing silver from the doors or the iconostasis would have created a huge uproar in the city.
Here's an example of a set of Byzantine bronze doors now in Rome. They are inlaid in silver and gilded.