So we find Bulgaria at the beginning of the 8th century still dangerously positioned on what was so recently Byzantine land, sandwiched between one of the great empires of the day and a vast and dangerous steppe full of volatile tribes. But the new Bulgarian state had just survived what history has shown time and time again to be one of the most dangerous moments of statehood: a transition of power.

Here, you can find a very high quality video documentary on the 717-718 Arab Siege of Constantinople by the Youtube channel Kings and Generals.