Imad Boles on the Historical Period When the Relics of St. Mark Were Taken from Egypt

From Comments at Roger Pearse's Site - Imad Boles is chairman of the British Coptic Association and he notes:

Egypt during the reigns of the Abbasid Al-Amin (809-813) and his brother Al-Mamun (813-833), who bitterly fought each other (reflecting a wider conflict between Muslim Arabs and Muslim Turks), suffered so many distresses. Absolute chaos ruled Egypt, and the country was divided between two major Muslim contenders, Al-Siri Abdel Hakam and Abdel Aziz Algirwi whose battles were mainly fought in the Nile Delta. The instability, terrorism and financial mismanagement that resulted destroyed Egypt. The situation was further compounded by the advent of fanatic Arabs from Andalusia and other areas, who seized Alexandria between 815 and 827, and persecuted the Copts and their Church. Abdullahi ibn Tahir (Abdallah ibn Daher, in Roger’s translation), dispatched by Al-Mamun in 826 AD, was able eventually, to conclude an agreement with the Andalusians to evacuate Alexandria and go to wherever they wanted outside Al-Mamun’s territory. They sailed out of Alexandria, and went to Crete, where they wrestled Crete from the Byzantines. Ibn Tahir left Egypt to Baghdad, the Caliphs city, on 20 October 827 AD. Eutychius’ sentence, “Abdallah ibn Daher returned to al-Ma`mun and reported about Egypt and on what he had undertaken (there),” relates to his expulsion of the Andulesians from Alexandria.

I think, though I have no direct evidence, that these Andalusians stole the body of St. Mark (the Copts always maintained that the head of St Mark was not taken) and took it with them to Crete. There, somehow, it is possible that they sold it to the Venetians. But the matter needs to be studied carefully.