4. Sassanian Empire (4th Century)
The Sassanian Empire rose to prominence in the 4th century, standing as Persia’s great power and Rome’s eastern rival. Renowned for its monumental architecture and vibrant urban centers, the Sassanians also advanced religious thought, notably Zoroastrianism. Their cultural and artistic innovations left a lasting mark on the Middle East and Central Asia (via World History Encyclopedia: Sassanian Empire).
