O wise one, know that Time unfolds in four great ages: first comes the Kṛta Yuga, followed by the Tretā, then the Dvāpara, and finally the Tiṣya, which is also known as Kali. Each age has its distinct nature: Kṛta is marked by the pure quality of sattva, Tretā by the energizing power of rajas, Dvāpara by a blend of rajas and tamas, and Kali, the last, by the dominance of tamas. In each age, the highest spiritual practice changes—meditation is supreme in Kṛta, sacrifice is celebrated in Tretā, pure worship in Dvāpara, and in Kali, giving alone is honored. The Kṛta Yuga spans four thousand years, with its twilight period and the lingering afterglow each lasting four hundred years. In this age, humans enjoyed lifespans of four thousand years, sustained even by eating stones, and when the age and its twilight passed, only a quarter of its original righteousness remained in the world. As the ages proceed, each is diminished: Tretā is three-quarters the length of Kṛta, Dvāpara is half, and Tiṣya (Kali) is half again. Their twilight periods also decrease: three hundred, two hundred, and one hundred years, with matching afterglow, in each successive age. In the beginning, during the Kṛta Yuga, dharma—righteousness—stood firmly on four feet, eternal and unwavering. In Tretā, it stood on three, and in Dvāpara, only two. By the time of Tiṣya, dharma was deprived of three feet, supported only by a remnant of sattva. In Kṛta, all things arose directly, and sustenance was full of pure essence. During the Kṛta Yuga, people were always satisfied and enjoyed all happiness. There were no distinctions of high or low among them; all were auspicious. Their lifespans, happiness, and forms were equal, and their love for one another was constant. There was no conflict, no hatred, and no fatigue. They dwelled freely on mountains and in oceans, without fixed abodes, free from sorrow, abundant in sattva, and single-minded in their pursuits. Their actions were without desire, their minds ever joyful; in this age, there was no division of good or evil deeds. The social orders of varṇa and āśrama existed, but there was no intermingling. The abundance of pure essence that sustained life began to diminish with the coming of Tretā, as Time exerted its influence. When the perfection of Kṛta faded, another form of perfection arose. As the subtlety of water returned, it came from the nature of clouds. From clouds and thunder, rain began to fall, and with a single rainfall, the earth was saturated. From this, wondrous trees known as "house-trees" sprang up, providing all means of sustenance and enjoyment. At the dawn of Tretā Yuga, people lived from these trees, but after a long time, a reversal occurred among them. Passion and greed suddenly arose, and because of this, all the house-trees perished. When these trees were gone, the bewildered people began to be born through sexual union. Yet, even then, those devoted to truth meditated upon perfection, and for them, the house-trees appeared once more. From these trees they obtained garments, fruits, and ornaments, as well as things endowed with fragrance, color, and taste. Honey, as strong as the earth, was found in every cluster, and by this, they lived happily and long. Through this accomplishment, the people were joyful, nourished, and free from suffering. But in time, greed overtook them again. They seized the trees and honey by force, and because of this, the wish-fulfilling trees and honey disappeared from the earth. When only a little of that perfection remained, the force of Time brought about the next change. With the turning of the Tretā Yuga, pairs of opposites arose—intense cold, rain, and heat—and people became greatly afflicted. Troubled by these dualities, they fashioned coverings and built shelters upon the mountains to ward off the harshness of nature. Formerly, they wandered as they pleased, but now, driven by need and desire, they began to live in homes. Afflicted by these dualities, they considered new means of livelihood, for the wish-fulfilling trees and honey had disappeared. Beset by disputes, thirst, and hunger, another accomplishment appeared for them in the Tretā Yuga. A new means of sustenance arose, with rain coming as desired, and from this rain, streams and other waters came into being. Due to the continuous rainfall, flowing streams appeared, and rivers began to course through the land. The droplets of water that fell upon the earth, merging with the soil, gave rise to medicinal plants. Then, fourteen types of trees and shrubs, both wild and domestic, seasonal and perennial, blossomed and bore fruit. These various trees and medicinal herbs appeared, and with their help, living beings subsisted in the Tretā age. Yet again, passion and greed arose among the people in every way, as was destined in the Tretā Yuga. Thereafter, they seized rivers, fields, mountains, trees, shrubs, and medicinal herbs by force, each according to their strength. Consequently, those fourteen medicinal herbs perished, and, considering this, they entered into the earth itself. Thus, Oṣadhyaḥ—the herbs—became united with Pitāmaha, the Grandfather. In this way, the progression of the ages unfolded, each bringing its own qualities, challenges, and ways of life, as ordained by the great wheel of Time.