Which major event marked the final end of the roman empire? splitting the empire into eastern and western empires the rise of constantine constant civil wars the invasion of rome by the visigoths in 476

The correct answer is "the invasion of Rome by the Visigoths in 476 CE.

While the other two answers are part of the decline in the Roman Empire, the greatest contributing factor was the series of invasions from the Visigoths, also known as the Goth Wars. This caused the Western Roman Empire to officially end when Odoacer deposed of Emperor Romulus Augustulus and declared himself king of Italy.

unless they converted, many non-christians (mainly jews and muslims) were persecuted

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.