Final answer:
After the Five Good Emperors, Roman rulers weakened Rome's influence by internal mismanagement, external threats such as the Sassanids and barbarians, and moving the capital to Constantinople, leading to weakened defenses and declining military efficiency.
Step-by-step explanation:
The Roman rulers who succeeded the Five Good Emperors contributed to the decline of Rome through various internal and external factors. Internally, leadership quality deteriorated as the Praetorian Guard auctioned off the throne, emperors were assassinated, and elites retreated to their estates, leaving the state vulnerable. Externally, the threat of Sassanids from the East and organized barbarian groups from the North pressured the Empire. The shift of Rome's capital to Constantinople also focused its strength in the East, contributing to the weakening of the West.
Additionally, economic and social changes such as the rise of Christianity and population growth amongst the barbarians led to tensions and instability. Rome's fall was a complex process, but the influence of its rulers during this time cannot be underestimated. The capture of Emperor Valerian, the rebuilding of Rome's walls to defend against Germanic invaders, and the overall decline in military efficiency and unity weakened Rome's power and influence significantly.