Let us journey through the sacred reckoning of time as revealed in the scripture. In the realm of the ancestors—those revered forebears who dwell in the subtle worlds—a month is counted as a single day and night. This division of time is carefully explained so that we may understand their measure. For them, thirty human days comprise a month; thus, what we call a month on earth is a day and night for the ancestors. Their year, too, is understood by translating our human calculations into their own. Here, three years of the ancestors are counted, and these are indeed their years. All this is measured by the worldly standard, and the year that is called human is remembered as such. Turning to the divine realm, the gods too have their own division of time: for them, a year is made up of a day and a night, and this division is explained once more. The periods of day and night in the divine realm are enumerated, and it is taught that one hundred human years are equal to three divine months. Thus, the divine year is described according to the human calculation. Beyond this, thirty years are considered to be the year of the Saptarṣis—the seven great sages. And ninety years are regarded as the year of Dhruva, the steadfast star. A hundred years, then, should be understood as the divine rule. It is said that there are three niyutas—vast numbers—of human years. Those skilled in calculation declare that a thousand divine years are counted in this way. The reckoning of the number of yugas—the great ages—is established according to the divine measure. There are fourfold divisions: Kṛta, Tretā, Dvāpara, and Kali. Dvāpara and Kali, too, are considered yugas. For each yuga, the period of twilight, the portion of twilight, and the duration equal to twilight are specified. These periods proceed in the same manner, counted in thousands and hundreds. Specifically, three hundred and two hundred are the twilights, and their portions are equal to those. For that, the twilight is one hundred, and the portion of twilight is equal to the twilight. Thus, the fourfold divisions of Kṛta, Tretā, Dvāpara, and Kali are established. Now, let us hear the years of the Kṛta Yuga. Forty thousand years, and likewise other periods, constitute the Kṛta Yuga. The Tretā Yuga spans eighty thousand years. The Dvāpara Yuga lasts for twenty thousand years, and the Kali Yuga endures for sixty thousand years. The yugas are certainly calculated as six times sixty hundred thousand. The portion of twilight for the four yugas is twenty thousand. The period joined with Kṛta, Tretā, and the others is called a Manvantara—a vast epoch presided over by a Manu. Thirty crores of years are declared according to human reckoning, and twenty thousand is this period, with a little more, not less. This period of a Manvantara, together with the yugas, has been described. Now, let us speak of what remains of the Tretā Yuga, as well as the Dvāpara and Kali Yugas. These two yugas, which come in order, have not yet been told. At the beginning of the Tretā Yuga, Manu and the seven sages existed. The connection with wives, the Agnihotra sacrifice, and the collections of the Rig, Yajur, and Sama Veda were established. The dharma transmitted through tradition, and the characteristics of proper conduct, were set forth—by truthfulness, celibacy, study of the scriptures, and austerity, indeed. In the first Tretā Yuga, these practices were observed by the seven sages and Manu, as well. Thus, the sacred division and progression of time, the yugas, and the establishment of dharma are revealed, guiding us through the cosmic cycles and the unfolding of righteousness.