Premise: Seyyid Kasim Gubari of Diyarbakır is recorded as being responsible for much of the calligraphy of the Sultan Ahmed Mosque (the "Blue Mosque") in Istanbul, he was commissioned to write verses from the Quran throughout the mosque. He was also said to be one of the greatest calligraphers of his day.
Hypothesis: Seyyid Kasim Gubari is famous for his work in the Red Square.