Origin/History :-
The Manikundram Temple, originally constructed in the 7th century, was later reconstructed during the Vijayanagara period, specifically between the 16th and 17th centuries. The temple features an Upanam and Adhistanam in its sanctum, though the Koshtams are empty. The Prastharam includes a Kabotham with a Nasikoodu, and the Sikaram is rounded. The Vimana over the Sanctum is referred to as Manikoodam.
The temple is managed by the Thanjavur Palace Devasthanam. Fragmentary Tamil inscriptions from the 16th to 17th centuries are found on the temple walls. An 1892 CE inscription tablet installed on the steps details renovations, including paving of the Praharam floor, and the construction of the Balipeedam, Garudan Sannidhi, doors, and compound wall. It also mentions similar works at the Sri Kalyana Venkatesa Perumal Temple, though its location is not specified. Maha Samprokshanams were performed on 16th March 2000 and 21st March 2022.
Puranic Significance :-
According to legend, Sage Parasara Maharishi and his disciple lived in an ashram on the banks of the Manimuthar River, now known as the Vennar River. The demons Thanjaka, Thandeka, and Tharakasuran troubled the sage and disrupted his Yagam. In response, the sage prayed to Lord Shiva for protection. Lord Shiva sent Kali, an incarnation of Goddess Parvati, to aid the sage. Kali killed Tharakasuran but could not defeat Thanjaka and Thandaka.
Sage Parasara then sought Lord Vishnu's help. Vishnu manifested as Narasimha (the lion-faced avatar) and vanquished Thanjaka. Following this, Vishnu settled in Yazhi Nagar. Thandaka, hiding in Patala Loka, was subsequently defeated by Vishnu in his Varaha (boar) form.
After these events, Lord Vishnu appeared before Sage Parasara as Neelamega Perumal. In this form, Vishnu is accompanied by Goddess Lakshmi, who sits on his left lap. In Yazhi Nagar, however, Lakshmi sits on Vishnu's right side, reflecting his more fearsome appearance.