In the early fourth century, the Roman Empire officially embraced Christianity. It now faced a new geopolitical adversary: the Sassanid Persian Empire, where Zoroastrianism was the state religion.

After the fall of the Arsacid Empire, the Sassanids created the Persian Empire ... Perhaps the mightiest of the Sassanid rulers, Shahpur remains as the last great emperor of ancient Persia ...

The Battle of al-Qadisiyah was fought in Mesopotamia — in present-day Iraq — in the A.D. 630s between Arab Muslims and the army of the Sassanid Persian dynasty during a period of Muslim expansion.

Originally constructed to house the Roman Emperor Valerian after his capture by Shapur I, the structure played a crucial role in the Sassanid Empire’s history. Following a decisive Persian victory ...