Editing Constantinople (section)

=== Survival, 565–717: Constantinople during the Byzantine Dark Ages ===
In the early 7th century, the [[Avars (Carpathians)|Avars]] and later the [[Bulgars]] overwhelmed much of the [[Balkans]], threatening Constantinople with attack from the west. Simultaneously, the [[Persia]]n [[Sassanid]]s overwhelmed the Prefecture of the East and penetrated deep into [[Anatolia]]. [[Heraclius]], son of the [[exarch]] of Africa, set sail for the city and assumed the throne. He found the military situation so dire that he is said to have contemplated withdrawing the imperial capital to Carthage, but relented after the people of Constantinople begged him to stay. The citizens lost their right to free grain in 618 when Heraclius realized that the city could no longer be supplied from Egypt as a result of the Persian wars: the population fell substantially as a result.<ref>Possibly from the largest city in the world with 500,000 inhabitants to just 40,000–70,000: The Inheritance of Rome, Chris Wickham, Penguin Books Ltd. 2009, {{ISBN|978-0-670-02098-0}} (p. 260)</ref>
[[File:Chora_Church_Constantinople_2007_panorama_002.jpg|thumb|left|280px|[[Chora Church]] medieval Byzantine Greek Orthodox church preserved as the Chora Museum in the Edirnekapı neighborhood of [[Istanbul]]]]

While the city withstood a [[Siege of Constantinople (626)|siege]] by the Sassanids and Avars in 626, Heraclius campaigned deep into Persian territory and briefly restored the ''status quo'' in 628, when the Persians surrendered all their conquests. However, further sieges followed the [[Byzantine–Arab Wars|Arab conquests]], first from [[Siege of Constantinople (674–678)|674 to 678]] and then in [[Siege of Constantinople (717–718)|717 to 718]]. The [[Theodosian Walls]] kept the city impenetrable from the land, while a newly discovered incendiary substance known as [[Greek fire]] allowed the [[Byzantine navy]] to destroy the Arab fleets and keep the city supplied. In the second siege, the second ruler of [[Bulgaria]], [[Tervel of Bulgaria|Khan Tervel]], rendered decisive help. He was called ''Saviour of Europe''.<ref>{{Cite web |title=Exposition, Dedicated to Khan Tervel |url=http://www.programata.bg/?p=62&c=1&id=51493&l=2 |url-status=dead |archive-url=https://web.archive.org/web/20160507131353/http://www.programata.bg/?p=62&c=1&id=51493&l=2 |archive-date=2016-05-07 |access-date=2014-08-28 |website=Programata}}</ref>