Who was the Byzantine Emperor during the height of the empire?

Justinian I was the Byzantine Emperor during the height of the empire, which is often associated with his reign from 527 to 565 AD. His rule is notable for significant achievements that strengthened the Byzantine Empire both territorially and culturally.

One of Justinian's major accomplishments was the codification of Roman law, resulting in the "Corpus Juris Civilis" or "Body of Civil Law," which laid the foundation for legal systems in many modern nations. In addition to his legal reforms, Justinian sought to reconquer lost territories of the Western Roman Empire, reclaiming parts of North Africa, Italy, and Spain. His military campaigns, led by generals like Belisarius, temporarily expanded the boundaries of the Byzantine Empire.

Justinian also oversaw a remarkable period of law and architecture, commissioning structures like the Hagia Sophia, which exemplifies the height of Byzantine architecture and remains a testament to the empire's artistic and cultural achievements.

While other emperors listed made notable contributions during their reigns, none reached the same level of influence and territorial expansion as Justinian, marking his time as the pinnacle of the Byzantine Empire's power and prestige.