Why did Edward Gibbon choose to write about the decline and fall of Rome?

Edward Gibbon’s decision to write The Decline and Fall of the Roman Empire was sparked on October 15, 1764, while he was "musing amid the ruins of the Capitol" in Rome.1

His motivation was driven by several intellectual and philosophical factors:

• Inspiration from Classical Ideals: Gibbon viewed the Roman Empire as a single entity that suffered an "undeviating decline" from the ideals of political and intellectual freedom found in the classical literature he had studied. He perceived the material decay of Rome as both a symbol and an effect of moral decadence.23
• Philosophical Perspective: Writing as an 18th-century "philosopher," Gibbon sought to treat religion as a phenomenon of human experience rather than divine revelation. He famously characterized the collapse of the Greco-Roman world as the "triumph of barbarism and religion," viewing the transition as a retrogression.3
• Historical Analysis: Gibbon believed the causes of Rome's fall were "simple and obvious." He argued that the empire’s "immoderate greatness" led to its inevitable collapse, suggesting that prosperity had ripened the principles of decay and that the empire eventually yielded to the pressure of its own weight.4