The Holy New Martyrs Emperor David the Great Komnenos together with his three sons and his nephew Alexios were killed by Mehmed II in 1463, and they are commemorated by the Church on November 1st. Below is an interesting letter by Ecumenical Patriarch Sophronios from the year 1472 that describes his death and a much treasured Cross that he carried on him at the time of his death.
Sophronios, by the grace of God Archbishop and Ecumenical Patriarch of New Rome and Constantinople, may grace, peace and mercy be to everyone through God Almighty: first kings and princes, magnates and officers, archpriests and bishops, abbots and priests, and finally simply everyone.
Let it be known to all that when the our home city, the queen of cities, the seat of the emperors, the city that is of Constantinople, fell, many holy things of the faith were destroyed shamelessly by the godless Turks including icons of the Virgin Mary and all the saints, as well as holy objects such as vessels and Bibles, precious stones, and other such holy things. Witnessing all of it, we wretched men struck our chests and were dumbfounded crying rivers of tears wearied by gasps due to unbearable grief. Not long after, the city of Trebizond, a great and famous city, the seat of an emperor, was taken itself by the godless Turks and was enslaved most bitterly, while all of its well-born men were brought to the city of Constantine, along with them David, emperor of Trebizond. After a few days had passed, the infidel killed him along with his three sons, while all his belongings passed to the lord of the Turks. In this seizure, a cross came into the hands of his head doctor Jacob, who was previously a Jew, though he later became a Turk.
This cross is crafted of pure gold with four parts and on each part five hyacinth stones making the pattern of a cross. Altogether there are twenty stones and on each part besides the stones already mentioned there are two pearls, eight altogether. On the fourth part of the cross in the middle there are four big stones which were sphere-shaped when discovered. In the very middle of the cross there is a very expensive stone, hard to come by as only emperors can possess it, for it is filled with great grace and colors, of such beauty and intricacy that anyone who sees it is amazed, as we were ourselves astounded seeing it. Below it hangs a sphere-shaped, golden encolpion having within one of the iron nails that nailed into the flesh of Christ. The letter inscribed on the encolpion reveals their faith. On one side of the said stone it reads: "This stone shall give you much bravery, stranger, if you deem to follow in its very footsteps." The other side bears the name of the great deed doer and emperor Alexios Komnenos, since the said cross was made for him. That it is an iron nail in the encolpion is born witness to from the precious stones. Outside of the cross, there is a silver chest on which the front face is inscribed "Christ Conquer", while on the back there are four letter Epsilons for Euren Eurema ek Theou Elene “Helen a discovery made with God.” It is also written on the four faces. In the middle, it has a two headed eagle, which is an imperial insignia, while below the eagle, there are two letters A.K. for Alexios Komnenos.
This infidel had the cross in his hands, when an officer of well-born station, not without his share of supreme virtue, reverent of the divine on high, named George Polos, came to him learning about the cross completely consumed by desire to get it out of lawless hands to get it into the hands of a most Christian lord so that the divine might not be in the hands of the impure. For this reason, he bought it with much effort at great expense from him having now taken possession of it. Having come to our Modesty, he begged and asked us to give him our written confirmation over the said cross because it is an imperial item and it is precious to emperors, quite correctly so. We bear witness to it being truly of Alexios the great emperor, while we have discussed in brief its forms and position in brief above. For the credit of all those who encounter it, the present confirmatory letter was issued by our Modesty to the well-born officer, sir George Polos in the month of August. Dated August ind. 12 in the year 6982 (1472).