Answer: Army and religion.
Step-by-step explanation:
These are two factors that most historians agree have partly led to the weakening and fall of the Western Roman Empire. In the last decades of the Western Roman Empire, there was a practice of hiring military mercenaries. They participated in the fighting for money as mercenaries. This practice was bad since these soldiers were not as effective as the regular Roman army. Therefore, Rome was much weaker on the battlefield. Religion is another big factor. With the spread of Christianity, society did not pay much attention to life on earth. Many rejoiced in the blessings promised to them in the Bible after death. Such an attitude has led to the weakening of all institutions.