Amongst the Shiva temples of Kongu Naadu (Kongu ezhu sthalangal), the one at Karur or Karuvur is renowned for its great history, vastness of size and elaborate plan. The Pashupathi Nathar temple at Karur is known for its tri-glories - Moorthy (the presiding deity), Sthalam (place of divinity) and Theertham (the holy water).
The temple is spread over an area of approximately 2.65 acres. The temple tower or the Raja Gopuram has seven tiers and seven 'kalashas'. The inner tower is a five-tiered one. The Raja Gopuram is embellished with beautiful sculptures depicting stories from the Thiruvilayaadal, Dashavatharam etc. Between the two towers is the Pugatchozhar Mantapam. Pugatchozhar is the 40th of the 63 Saivite Saints, known as nayanmaars. He was a king, who ruled the kingdom of Karur and later surrendered himself to the service of the Lord. Karuvur was also the birthplace of the great Eripattha Nayanaar, the 8th in the line of nayanmaars. The temple has a majestic outer wall. It measures 465 feet, east-west and 205 feet, north-south. The front gopuram is 120 feet tall. The temple has two circumambulatory passages or 'praahaarams'. The 'nootrukkal mantapam' (100-pillared hall) is an architectural highlight and a must-see.
The lord 'Kalyana Pashupathi Nathar' facing east is self-manifested as a 'Swayambhu Lingam' and also goes by the name 'Aanilayappar'. The lingam is about 2 ft tall and appears slightly tilted to the north. It is a noteworthy feature that the sun's rays fall on the lingam during the 14-15-16th days of the Tamizh month of Panguni (mid Mar-mid Apr), when the special Panguni Uthiram festival is held. Lord Aanilayappar embodies the holy trinity of Brahma, Vishnu and Shiva. The lower section of the lingam represents Lord Brahma and is called Brahma baagam, the middle represents Lord Vishnu and the upper section represents Lord Maheshwara in the Uthira Bagam.
Facing the shrine are the flagstaff (kodimaram or dhwajasthambham), the customary sacrificial altar and an idol of Lord Nandi. The southern corridor of the inner passage houses the 63 nayanmaars. There is a separate shrine of importance for Eripatha Nayanaar. The western corridor is adorned with the statues of Lord Vinayaka, Lord Muruga and Goddess Gajalakshmi. The northern corridor has the 'panchalingas' or the 5 special lingas.
A short walk towards north, from the main shrine leads you to a gateway, and onto the shrine of his consort, Sundaravalli Amman, facing south. She is an embodiment of Kriya Shakthi, prodding and motivating her devotees into 'thinking on their toes' and engaging in fruitful action. To the left of this, is the old, rustic shrine of Alangaravalli Amman, facing the eastern direction. She is GnanaShakthi, the epitome of the 'power of knowledge'.
Hindu mythology is rife with stories of Lord Brahma, Kamadhenu (the divine cow) and other devataas worshipping this lingam here. 'Aa' means 'cow' in Tamil. Aanilayappar gets his name since Kamadhenu worshipped him here, with libations of her milk, directly from her udder. When Kamadhenu moved, her hoof hit the lingam and the dent caused thereby can still be seen.
It is said that Muchukundha Chakravarthy from the Skanda Puranam period had also lived and served the lord in this sacred place. In the south-west corner (kannimoolai) of the southern corridor is a sannidhi dedicated to Karuvur Siddhar, one among the 18 holy siddhars. History espouses that Karuvur Siddhar lost his physical body here and became 'one with the lord'.
The 14th century BC Tamizh poet Arunagirinathar of Thiruppugazh fame also came to Karuvur and sang in praise of the Muruga here. 7 verses or pathigams are found in the Thiruppugazh, all in praise of Karuvur Murugan. The lord appears facing east, in a standing posture, with 6 radiant and merciful faces, 12 pairs of valorous hands and two beautiful consorts, Valli and Deivaanai. His peacock is found to his back.