Uthirakosamangai, also known as Mangalanatha Swamy temple, is a Shaiva temple situated near Ramanathapuram in the Ramanathapuram district of Tamil Nadu. The temple is much older and the structure as it exists today is believed to be built by the Pandya kings, Achutappa Nayak (1529–1542 CE), Muthuveerappar and other kings of Ramanthapuram at various times. The temple has been glorified by the hymns of 9th-century saint Manickavasagar and 15th-century saint Arunagirinathar.
The temple is considered sacred along the lines of Ramanathapuram, Sethu Madhava Theertham and Lakshmana Theertham. The temple is a prominent tourist destination of Ramanathapuram district. The temple has numerous shrines, with those of Mangalanathar, Mangalambigai and Natarajar being the most prominent. The temple houses a 6 ft (1.8 m) tall ancient maragatha Nataraja idol carved out of emerald, being the one of its kind. The temple has six daily rituals at various times from 5:30 a.m. to 8 p.m., and six yearly festivals on its calendar. The temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.
As per Hindu legend, once hundreds of rishis (ascetics) performed penance worshipping Shiva. Shiva told the rishis that he would appear in the form of a fireball to acknowledge the penance of Mandothari, the wife of king Ravana in Sri Lanka. Shiva appeared in the form a small child in Ravana’s palace. Ravana lifted the beautiful child and there was a small wound out of it. Simultaneously, there was a fireball out of the Agni Theertham (temple tank), which the rishis felt were on account of Shiva attacking Ravana. Out of thousand, 999 killed themselves by falling in the fire, while one of them remained to save the vedic books. Shiva was pleased by the rishi and appeared as Sahasralingam (thousand lingams) for the 999 and one more for himself in the temple. The single rishi was believed to have emerged later as Manickavasgar in his later birth.
Uthira Kosa Mangai is a tiny hamlet. It is considered to be one of the very ancient Hindu temples which Tamil literature describes as “Mann Mundhiyo Mangai Mundhiyo?” meaning “Did the mud (mann) come first or is the Mangai (The Female Deity of the Temple)?”. This is the place where Siva transferred the secrets of Vedas to Parvati. Uthiram means (upadesam) kosam (secrets) Parvati (Mangai) hence this place is known as Uthira Kosa Mangai. The temple is believed to be built by the Pandya kings. Achutappa Nayak (1529–1542 A.D.), a Hindu ruler of Thanjavur, Muthuveerappar and other kings of Ramanthapuram Sethupathy dynasty have contributed to the temple. The last renovation was carried out by the queen of Ramanthapuram. The temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.