The deity at Simhachalam, the lion-man incarnation of Lord Mahavishnu is usually covered with sandalwood paste. The original shape of the deity in the Tribhanga posture has two hands with the head of a lion on a human torso. An inscription dated as far back as 1098 AD of the Chola king Kuloththunga provides some clue as to its antiquity. Another inscription shows a Queen of the Eastern Ganga of Kalinga (ancient Orissa) (1137-56 AD) covering the image with gold while a third inscription says the eastern Ganga King of Orissa Narasimha Deva built the main/central shrine in 1267 A.D. With more than 252 inscriptions in Oriya and Telugu describing the antecedents of the temple, it is a historically important monument.
Sri Krishna Deva Raya after defeating the Gajapati ruler of Orissa Gajapati Prataparudra Dev visited the shrine twice in 1516 AD and 1519 AD and offered numerous villages for maintenance of bhogam (worship) along with valuable jewellery of which an emerald necklace is still in the temple. For the last three centuries, the Royal family of Vizianagaram,” The Pusapati Gajapathi’s” have been the temple’s trustees.
The exact age of the temple is not known, but it contains an inscription, dated as far back as 1098-99 A.D. of the Chola king Kulottunga-I, who conquered the Kalinga territories, and it must thus have been a place of importance even by that period. Another inscription shows that a queen of the Velanandu chief Gonka III (1137-56) covered the image with gold a third says that the Eastern Ganga king Narasimha.
The Simhachalam temple still contains in inscriptions left here by Sri krishna Devaraya of Vijayanagara empire recounting his successes and relating how he and his queen presented the yod with necklace of 991 pearls and other costly gifts.
Architecturally the temple apparently deserves high praise. This temple contain a square shrine surmounted by a high tower, a portico in front with a smaller tower above it, a square sixteen pillared mandapam (called the mukhamandapam) facing this, and an enclosing verandah, all made of dark granite richly and delicately carved with conventional and floral ornament and scenes from the Vaishnavite puranas. Some of the carvings are mutilated (by Muhammadan conquerors, it is said). One of the pillars is called the kappa stambham or 'tribute pillar'. It is credited with great powers of curing diseases and granting children. In the verandah is a stone car with stone wheels and prancing stone horses.
Outside this inner enclosure there is the excellent natyamandapam on the north side of the temple, where the god's marriage is performed. This is supported by 96 pillars of black stone, arranged in sixteen rows of six each, which are more delicately carved than any others in the temple, are all different in the details of their design, and yet avoid incongruity of effect by adhering to one general type - especially in their capitals, which are usually of the inverted - lotus shape.
The deity is kept covered with an unctuous preparation of sandal paste. Once a year i.e, on akshaya thritheeya day (3rd day of Vaisakhamasam) this sandal paste will be removed in a ceremony at the festival called Chandanayatra (Chandanotsavam) and Nija roopa darsanam of Swamy Vari will be provided to devotees. It is the most important festival in this temple.