Just war theory is the belief that war is morally or legally justified. There are four most important principles, also known as belief, principle, or creed, from St. Augustine's just war theory. Saint Augustine was born in 354 AD and adopted the doctrine of Christianity in 386 AD during the decline of the Roman Empire. St. Augustine believed that everything was made by God; therefore everything that is made is good and perfect. St. Augustine believed that evil was due to the fall of man, who introduced sin into the world. Before the fall of man, there was no death, disease, or suffering in the world. St. Augustine understood that war was the result of the fall of man and the introduction of sin into the world. St Augustine had accepted “war and violence as legitimate means of attacking subjective evaluations of evil” (Christopher p42). St. Augustine had four important principles which are: “(1) There must be a just cause; (2) Wars must be declared and conducted by the competent authority; and (3) the ultimate goal must always be peace. Furthermore, Augustine insists that soldiers should...