Soon after the time of Açoka, the great Buddhist emperor of the third century before Christ, India became the theater of protracted invasions and wars. Vigorous tribes from the North conquered the region of the upper Pan jab and founded several states, among which the Kingdom of Gandhâra became most powerful. Despoliations, epidemics, and famines visited the valley of the Ganges, but all these tribulations passed over the religious institutions without doing them any harm. Kings lost their crowns and the wealthy their riches, but the monks chanted their hymns in the selfsame way. Thus the storm breaks down mighty trees, but only bends the yielding reed. By the virtues, especially the equanimity and thoughtfulness, of the Buddhist priests, the conquerors in their turn were spiritually conquered by the conquered, and they embraced the religion of enlightenment. They recognised the four noble truths taught by the Tathâgata: the prevalence of suffering which is always in evidence in this world; the origin of suffering as rising from the desire of selfishness; the possibility of emancipation from suffering by abandoning all selfish clinging; and the way of salvation from evil by walking in the noble eightfold path of moral conduct, consisting in right comprehension, right aspiration, right speech, right conduct, right living, right endeavor, right discipline, and the attainment of the right bliss.