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.
I built the central shrine,the mukhamandapam,the natyamandapam, and the enclosing verandah in black stone in the later half of 13th century and other grants inscribed on its walls (the Government Epigraphist's lists for 1899 give not less than 125 such inscriptions) make it a regular repository of the history of the district.
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.