When Lord Rama sent the pregnant Sita away, she took refuge in Sage Valmiki’s ashram in the forest of Veesharanyam, now Koyambedu. Sita gave birth to twins, Lava and Kusa, who lived as hermits. During an Aswamedha Yagna, Rama's horse reached Kosai Nagar (Koyambedu). Lava and Kusa captured the horse, leading to a fierce battle with Rama's battalion, including Bharatha, Shatrughna, and Lakshmana, all of whom were defeated by the boys. Rama himself battled them until Sage Valmiki revealed their identities. Rama stayed here as Vaikundavasa Perumal, with several sculptures depicting these events. The temple has an unfinished Rajagopuram, a bali peedam, and a tall copper-plated Kodi Maram. Notable are three closely arranged trees, symbolizing Siva, Parvathi, and Narayana. The main deity, Vaikundavasa Perumal, stands with Sri Devi and Bhu Devi, and a rare idol of Vaikhanasa Maharshi is present. There is a unique sannidhi for Rama and Sita, shown in simple attire from their forest exile, and a rare depiction of pregnant Sita with Lava and Kusa and Sage Valmiki. Thayaar Sri Kanagavalli and Sri Andal also have separate shrines.