Constantine IV, Pogonatus
July 15 668 through July 10 685
 
During his reign the Arabs made their first siege of Constantinople that would last for several years and stem the tide of European invasion from the Arabs.  Constantinople lived up to its original usage as being the "gate keeper" of Europe.  His two brothers, Heraclius and Tiberius, co-ruled with him until in 681 Constantine IV deposed them and died at an early age in 685, with his son Justinian II as successor.