"The Decline and Fall of the Roman Empire" refers to the gradual process through which the vast Roman Empire weakened and eventually collapsed. This decline began in the 3rd century AD, marked by political instability, economic troubles, and military defeats. Factors such as corruption, overexpansion, and invasions by groups like the Visigoths and Huns contributed to the empire's fragmentation. By the late 5th century, the Western Roman Empire officially fell when the last emperor, Romulus Augustulus, was deposed in 476 AD. Meanwhile, the Eastern Roman Empire, known as the Byzantine Empire, continued to thrive for nearly another thousand years, preserving much of Roman culture and governance.