The construction time of Koneswaram has been estimated by comparison between carved reliefs on the temple's ruins, literature on the shrine and the inscriptions commonly used in royal charters from the 5th to 18th centuries. Koneswaram was likely founded before 400 B.C., although its exact date of birth remains vague. The evidence extant attests to the shrine's classical antiquity. Construction of Hindu temples was made possible due to the prevalent faith amongst the locals and mercantile communities in the region during the Sangam period. Kaviraja Varothiyan's Tamil poem inscribed on the "Konesar Kalvettu", the 17th century stone inscription chronicle of the temple, gives the shrine's date of birth as circa 1580 B.C. Archaeologists point to its initial phase consisting of a rock cave, multilayered brick shrine style popularly constructed to Tamil deities of a range of faiths during the Sangam period (see Religion in ancient Tamil country).