Question

Which politician changed the Roman constitution so much, especially weakening the plebeian tribunate, that it was never the same again?

Answer 1

Lucius Cornelius Sulla the Roman dictator was the one responsible for the dramatic changer in Roman consitution. Sulla's politics was rather conservative, and Sulla had an objective to strengthen the Roman Senate and reduce the power of the plebeian tribunes. He retired in 79BC.