Roman Empire and Sasanian Empire

The Roman Empire was a state that dominated the Mediterranean and much of Europe, Western Asia, and North Africa during the classical period. The Roman Republic had previously conquered most of these territories, which later came under permanent single-person rule following Octavian's rise to power and the establishment of the Augustan Principate in 27 BC. By the late 3rd century AD, the empire had been divided many times. The Western Roman Empire collapsed in 476 AD, whereas the Eastern Roman Empire (also known as the Byzantine Empire) persisted until the fall of Constantinople in 1453.

The Sasanian Empire, officially Eranshahr (Middle Persian: 𐭠𐭩𐭥𐭠𐭭𐭱𐭲𐭥𐭩, romanized: Ērānšahr, lit. 'Empire of the Iranians'), was an Iranian empire that was founded and ruled by the House of Sasan from 224 to 651 AD (the era of late antiquity). Lasting for over four centuries, the length of the Sasanian dynasty's reign over ancient Iran was second only to that of the Arsacid dynasty of Parthia which immediately preceded it.