Somawathi Chaithya was built 2nd centaury BC and this stupa is said to enshrine the right Tooth Relic of Lord Buddha. The Somawathi Chaithya is located about 20 Km north east of Polonnaruwa, by the bank of the Mahaveli River within the Sanctuary. The flood plains of Mahaweli River have been inhibited by a large number of wild animals ranging from elephants, wild buffalo, deer and other animals.
This Chaithya had been abandoned more than fifteen years due to the threat of war. According to the ancient chronicles of Sri Lanka the very first Arahant of this country Ven.Aritta, visited the abode of gods and brought back to Sri Lanka the Sacred Relic Tooth of the Buddha. This a Sacred Relic was handed to king Giri Abha and his consort Queen Somawathie who was King Kavantissa’s sister. Queen Somawathie dedicated to construct a Stupa in adoration of the Buddha at Somapura with the consent of Arahath Mahinda and the King Giri Abha.
It is believed that one of the only two tooth relics of Buddha existing in the world is at the Somawathiya and the other one is at the Dalada Maligawa, Kandy. It is the very reason that thousand of pilgrims pay their hamage to this chaithya.
Archaeologists have four moonstones and flower pedestals excavating around the chaithya. In addition to these many buildings have been unearthed including a wall surrounding the stupa.
Out of the nine stone inscriptions found on the Eric Swan rock. This rock can be seen few meters before the main entrance to the temple. This rock was named Eric Swan Rock, because a photographer named Eric Swam, who was killed by a wild elephant near this rock.