Once on earth every kingdom was destroyed, the existence of mankind was in danger by not abiding the law of Dharma. Indian system is divided is four cast Brahman, Kshatriya, Vaishya & Sudra, all four are born from Adi Pursha's four parts. Brahmans are born from the mouth of the eternal Purusha, Kshatriya from hand & chest part, Vaishya from thigh & Sudra's from feet. Each one has a certain duties of their nature. Kashtriya reside as king & reign the kingdom by the law of Dharma. But at that time Dharma was not in nature anymore. Existence of Gods depend on the deeds of human, so they feared if mankind would be destroyed they will have no existence as well. They searched & found Divodas who was the only king abiding the law of Dharma living in forest of bliss. Gods asked him to reign Kashi & re-establish the earth on the law of Dharma. Divodas condition was that if only Gods will leave Kashi, he will reside on the throne of Kashi. Having no other option gods accepted his condition & let him reside on the throne of Kashi & left for Heaven. By his power of Dharma Divodas re-established the city. Everyone had everything in this city of Kashi & law of Dharma was established. Many years latter when gods craved to come to Kashi again they could find no way to enter in the city. They came in different forms to find a single fault of king & by violation of pact they will enter in city. Living few years in city they were conditioned by the law of Dharma & became residents of Kashi in Divodas kingdom. They forgot their virtues & followed Divodas. Finally lord Ganesha came & made king think that having everything in Kashi he has no mental peace. Lord Ganesha told him that ten days later a saint will come & soothe him from his distractions. Lord Vishnu came in disguise of saint & told him Oh! King undoubtedly you are the one who established Law of Dharma on earth again & saved it. You are the one who created every element by shear power of Dharma just to save earth. But just one deed of yours to ask Shiva to leave his beloved city is cursing your mental peace. By no means your deed is right. You need to correct it by making a Shiv Linga & worship him to come his city-Anandavan. King did the same & Shiva returned to his city.