Most Influential Byzantine Emperors/Figures

Name some and give reasoning. Lists are always welcome!

A3TG

Not sure when we're considering the Byzantine era to start, but here it goes:

Contstantine I - founded the city, reformed the army, made Christianity an ascendant religion among the political elite.

Justinian - his building projects enhanced the city, his legal Code (and other documents) influenced Byzantine law and law in many other states, he was one of the few emperors to expand the Eastern Empire's frontiers, his religious views set the tone for some time (though it alienated many)

Heraclius - officially retired Latin as a language of government, renamed his office "Basilius" (king), won brilliant victories against the Persians and lost critical provinces to the Arabs

Leo III the Isaurian - saved Constantinople from the Arab seige and turned the tide of the Arab offensive; started the whole Iconoclasm controversy

Constantine Porphyrogenitus - left us lots of useful treatises, histories, manuscripts, etc.

Basil II Bulgaroktonos - brilliant military leader, his reign was a high-point for the Empire in the middle of the Middle Ages

Alexius I Comnenus - called on the Pope to drum up military support for the Empire from Western Europe, thus playing a key role in the start of the Crusades

Manuel I Comnenus - good military leader until the Myriokephalon disaster; enamoured of Western ways and set a very different (Western European) tone in comparison to his predecessors

Those are some that stand out most to me.

Belisarius - One of the few who for the most part kept his head down and concentrated on the idea of empire and a return to days of old (and just doing what he was told to do as a good general). Many others would have given up on the retaking of Rome and Italy against such huge odds. His ability on the field rings like J. Caesars or Camillus. All this while Justinian rotted in court giving us nothing but buildings and compiling laws. Like the early consuls of the republic, Belisarius is remembered as a general and a leader, not on a list of failed emperors.

Julian - More interesting if he had have lived longer. More hyped up by the likes of Gibbons on the assumption of what may have happened had he ruled for 30 or 40 years. That said his short reign did show signs of a more Latin view of the empire. His distaste for extravagance and tax reforms were quite unlike his immediate predecessors and most of his successors. His paganism leads us to think of republic and days of old, but in the interest of cohesion and stability I think he would have had to rethink some of his ideas had he lived longer.

Probably each of the Angeli emperors - the level of corruption and the loss of bulgaria and Constantinople itself to the latins in 1204, would seal the fate of the empire, when it was retaken in 1261 - the empire would be only a shadow of its former self.

Mainly Justinian, Heraclius and Basil II.

Justinian (or rather his successful generals) gained again many parts of former Western Roman Empire. Heraclius saved whole empire from massive persian attacks and stabilised situation after bad rule of Phocas who almost ruined whole empire. Basil II was probably last emperor of really superpower. After his reign empire gradually decreased into local power, vasal state and city state finally.

I would echo the choices of Justinian I, Heraclius and Alexius I. But oh how much fortune, good and bad, played into the way their reigns played out.

Justinian had Belisarius, Amalasuntha, the Ostrogoths, Vandals and Lombards, and the plague. If Belisarius had been more politically astute and aware--if Amalasuntha had not offended the Goths and given Justinian an excuse, if the Vandals had not lost...But instead, Justinian did his best to reunite vast portions of the somewhat fragmented Empire in the West.

Heraclius did his best to bring the Empire back to glory after the debacle of Phocas, and the incursions of the Persians.

And Alexius--the poor man just wanted to be rid of those pesky Turks. Instead---he energized the Pope In Rome to start "Holy wars" the like of which still resonate today.

And Alexius--the poor man just wanted to be rid of those pesky Turks. Instead---he energized the Pope In Rome to start "Holy wars" the like of which still resonate today.

Yes, but practically only first crusade served its purpose.

If we are talking about influence due to actions, I would go for Romanus IV Diogenes. His bad judgement prior to and during the Battle of Manzikert started a trail of events which not only sealed the fate of the Eastern Roman Empire, but led to eventual supremecy of the Ottoman Sultanate in Eastern Europe, the drawing up of borders between nations which held sway until 1918,  and cultural/religious divisions evident in the Balkans to this day. The fall out from this battle also resulted in the subsequent conversion of the Seljuk Turks to Islam.

What about Constantine V?  Usually dismissed because of his religious policy, but lasted a long time and didn't do badly.