The First Golden Age was a century of relative peace and prosperity in the Kingdom of Hyrule's history lasting from the end of the Rise of Ganon (0 AG) until the onset of the Gerudo Wars (99 AG). As the era is not marked by conflict, it is not the subject of a Hyrule Historia arc, though the events of The Realm of Twilight occur during this time.
The first fifty years of the Golden Age were presided over by Princess Nylin Zelda I and her Prince Consort Arthon. During this time the Princess reunited and rebuilt a Kingdom shattered by Ganon's invasion. During this time she authorized Rauru to convert the Temple of Time into a portal to the Sacred Realm with the aid of the Oocca. Nylin passed away in 53 AG, and was succeeded by her daughter Yanera Zelda II. Yanera's fourty-four year rule would be marked by her restoration of diplomat ties with the Zora Dominion, which had broken down after Hylian involvement in freeing the Gorons from their Volvagian overlords during the Rise of Ganon. Throughout her reign she was able to maintain peace between the three peoples. Yanera Zelda died in 97 AG, and was succeeded by her daughter, Mahrala Zelda III, the last Princess to preside during the Golden Age. The third Zelda's reign would be plagued by scandal and strife. In her youth Mahrala had served as a diplomat for the Kingdom, and fallen in love with a Shiekah diplomat named Agahnim, and the two fostered a daughter in 85 AG. However, when she took the throne, Agahnim's Sheikah heritage was discovered and he was forced to magically erase all knowledge of the marriage- only his wife and daughter would remember him. During this time, the Hylian army also saw significant reforms, including the formation of the feared Ironclad Elites led by Commander Akazoo. When she took power, Mahrala struggled to maintain peace between an increasingly belligerent Zora Dominion and Goron Brotherhood, as the Gerudo began to push into Hyrule. Taking a contingent of troops to Ordona Province to investigate, she would discover that not only were the Gerudo invading, but that her former husband had seized power and sided with the Zora Dominion against the Gorons. The Gerudo Wars had begun.
The Golden Age also saw the birth of the Kokiri race. Amid the chaos of the Rise of Ganon, a group of Hylian bandits took over the old Hylian strongholds in the Kokiri Forest and Faron Woods, raiding the countryside and slaughtering local creatures. After years of terror, an Alliance of forest creatures led by the Great Deku Tree slaughtered the rogue Hylians, but spared their children. Kasuto set about an experiment to divorce these Hylian children of their animal instincts and bring them into harmony with nature, and by 10 AG the first true Kokiri had been born. The Kokiri would come to settle most of the Kokiri Forest and establish the short lived Kingdom of Faron in the south, which eventually fell due to their isolation from their father and Lizalfos attacks.
The First Golden Age was an era of decay for the waning Gerudo Empire, as their male population died off and resources went into decline. By 99 AG, only one known male had been born in a generation, and largely forced to interbreed with other cultures to bear children, the Gerudo faced the imminent extinction of their cultural heritage.