Leo III the Isaurian vs Nikephoros II Phokas

Leo III successfully defended Constantinople from a massive Arab siege by the Umayyad Caliphate. The siege lasted from 717 to 718. Leo used Greek fire and a harsh winter to defeat the Arab fleet and army, saving the Byzantine Empire from conquest and halting Arab expansion into Europe.

Leo III reorganized the Byzantine military and administrative system, strengthening the theme system. He created new themes and improved the defense of the empire. These reforms increased the empire's military effectiveness and administrative efficiency.

Leo III issued the Ecloga, a legal code that revised and simplified Roman law. The code was written in Greek and emphasized Christian principles, including greater protection for the poor and women. It influenced later Byzantine and Slavic legal systems.

Leo III issued an edict banning the veneration of icons, initiating the first period of Byzantine Iconoclasm. He ordered the destruction of religious images and persecuted iconodules. This policy caused deep religious divisions within the empire and strained relations with the Papacy.

Leo III led the Byzantine army to a decisive victory over the Umayyad Arabs at the Battle of Akroinon. The Byzantine forces destroyed the Arab army, ending the Arab threat to Anatolia for decades. This victory consolidated Byzantine control over Asia Minor.

Nikephoros II led a campaign that recaptured the island of Crete from the Arabs after a long siege of Chandax. This victory eliminated a major pirate base and restored Byzantine control over the eastern Mediterranean.

Nikephoros II Phokas was proclaimed emperor after the death of Romanos II. He was a successful general who had recaptured Crete. His accession was supported by the military aristocracy.

Nikephoros II launched a series of campaigns against the Hamdanid Emirate, recapturing Tarsus, Adana, and other cities in Cilicia. He also invaded Syria, capturing Aleppo in 962. These victories expanded Byzantine territory.

Nikephoros II was assassinated in his palace by a conspiracy led by his nephew John Tzimiskes and his wife Theophano. He was stabbed to death in his bedchamber. John Tzimiskes then became emperor.