A sample of what appears in the Real Messiah order it hereI will start by answering the last question on your note. Chatby coastline has dramatically changed since the 9th century. Depths have changed probably by 3 or 4 meters and after the construction of the Corniche coastal road and the heavy construction of all the suburb in the early 20th century it is no recognisable.
The only limited space that reminds of how the area looked is the Macedonian Necropolis of Chatby, which during the 9th century was covered with earth and the tombs were not visible.
At about a kilometre inland from the alleged site of the Martyrium of St. Mark there is the large surface of the Christian Cemeteries. This land was given in the early part of the 19th century to the Christian Foreign Communities of Alexandria and to the Copts so they could bury their dead outside the walls. The Jew had and kept using the very old Jewish grave yard, within the walls.
There was certainly some negotiation between the Khedival authority and the heads of the Christian Communities as to the best spot to be selected for the burials. Thinking loud I wounder if the fact that a number of martyrs had been buried there influenced the choice? Checking on the alleged martyrium existing on the land of the Coptic cemetery may shed some light. And I will do so in April/May. But there is a contradictory fact to advancing a theory that the area of the European cemeteries had been in proto-Christian years a site reserved for the burial of holy men. And that is that some 5 years ago Jean-Yves Empereur carried out an excavation in the Latin Cemetery to check if the Alabaster Tomb was part of a Ptolemaic Necropolis and at a depth of only some 5 or 6 meters a quarter of small modest dwellings of circa the 6th C. AD appeared. There were obvious marks of a destruction by fire.[?]..same remains of destruction are to be found in other parts of Alexandria for that same period at nearly the same depth. So people were living there...is this compatible with a religious centre with Martyrs burials?.
As to the questions if the Martyrium and the tombs would be guarded I would tend to say no. The church may have had a guardian. And I do not believe that the Muslim authorities of the city in decline that was Alexandria during the 9th century would be much concerned about the transport of any relics. But bribery was a custom through all the Middle Ages and the only concern of any customs official would be to levy some taxes [there were taxes on everything] and getting a baksheesh on the top.[Travellers relations]
If the remains of these holy-men had been transported through the Rosetta Gate to be placed in the Fondice of the Venetians waiting for the right time to be embarked on a ship there would be no way that the customs authorities would not notice it. Often Christian visitors where stripped of their cloths in order to have them thoroughly searched and taxed. Could the remains be loaded on a tender and then taken secretly on board a Venetian ship at anchor in the outer harbour of the Eastern Port.. that may have been possible but risky. As the ruder of any Christian ship was dismantled and taken ashore upon arrival in order to prevent a clandestine departure for avoiding the payment of taxes.... whatever we may say is conjectural.
