This belief in an age of innocence and bliss, by which the career of humanity began, is also to be met with amongst all peoples of Aryan or Japhetic race, and was theirs anterior to their separation, the learned having long agreed that this is one of the points on which Aryan traditions are most plainly derivable from one common source with those of the Semitic race, of which last Genesis affords us the expression. But with Aryan nations this belief was closely linked with a conception specially their own--that, namely, of four successive ages of the world; and we find this conception attain to fullest development in India. Created things, and among them humanity, are destined to endure for 12,000 divine years, each of which contains 360 years as reckoned by men. This enormous period of time is divided into four ages or epochs: the age of perfection, or _Kritayuga_; the age of the threefold sacrifice--that is, the perfect accomplishment of all religious duties, or _Trêtayuga_; the age of doubt or of the obscuration of religious notions, _Dvaparayuga_; finally, the age of perdition, or _Kaliyuga_, which is the present age, only to be brought to a close by the destruction of the world.[50] The Works and Days of Hesiod show us that precisely the same succession of ages was held by the Greeks, but without their duration being calculated by years, and with the supposition of a new humanity being produced at the beginning of each; the gradual degeneracy, however, which marks this succession of ages is expressed by the metals after which they are named--gold, silver, brass, and iron. Our present humanity belongs to the age of iron, and is the worst of all, although it began with the heroes. Zoroastrian Mazdeism also admits this theory of the four ages, and we find it expressed in the _Bundehesh_,[51] but under a form less nearly akin to the Indian conception than was Hesiod's, and without the same spirit of crushing fatalism. Here the duration of the universe is fixed at 12,000 years, divided into four periods of 3000. In the first all is pure; the good God _Ahuramazda_ reigns over his creation, in which as yet evil has not appeared; in the second, the evil spirit Angromainyus issues from the darkness in which he had up to this time remained inert, and declares war against Ahuramazda, and then begins their conflict of 9000 years, which occupies three of the world's ages. During the first 3000 years Angromainyus has but little power; during the second, the success of the two principles remains pretty evenly balanced; finally, during the last age, which is that of historic times, evil prevails, but this age is to terminate with the final defeat of Angromainyus, to be followed by the resurrection of the dead and the beatitude of the risen just. The advent of the prophet of Iran, of Zarakhustra (Zoroaster) is placed at the close of the third age, or exactly in the middle of that period of 6000