April 22, 1821 was (Orthodox) Easter Sunday and Ottoman Sultan Mahmud II, outraged at the Greek Revolt of March 1821, ordered the execution of the Orthodox Patriarch of Constantinople, Gregory V, who was hanged still in full Patriarchal vestment, from the main gate of his church.

Mahmud II initially secured a fatwa for the killing of all Greeks in the empire, but in the end "only" thousands were killed, including three other bishops, and many high-ranking Ottoman officials of Greek ethnicity, including the the Grand Dragoman, Konstantinos Mourouzis.

It was expected that the Patriarch and senior officials like the Grand Dragoman, could ensure the loyalty of their confessional community. And if not, there was a price to pay. The body of the Patriarch and bishops were dragged through the streets and thrown in the sea.

The Grand Dragoman was an exalted Ottoman diplomatic position (Dragoman originally from the Arabic ترجمان, translator) in a multi-lingual and multi-ethnic empire and had been held mostly by the Phanariot Greeks of Constantinople for over two centuries.

In addition to the massacres, many Istanbul Greek Orthodox churches were destroyed and damaged. Among them the famed Church of the Life-Giving Font of the Theotokos (the Sultan would give permission for it and others to be rebuilt a decade later).