The word Mihintalava means ‘Plain of Mahinda’. A Stupa was built in memory of this great Saint enshrining his bodily relics by King Uttiya in the second century B.C.
This Stupa is therefore regarded as one of the earliest monuments found in the hills of Mihintale, Kantaka Cetiya being one of them.
Bricks bearing Brahmi letters of the most archaic type of mason’s marks were found in debris and indicated an early date for the original foundation which is definitely ascribed to a period prior to the Christian era.
According to the Mahavamsa, a portion of Mahinda Mahathera’s ashes was deposited on the hill top of Mihintale and a Stupa was built to commemorate him. The rest of the ashes were deposited in several other places of the island and Stupas were built upon them.
According to an inscription discovered from Rajagala in the Ampara District it is clear that the ashes of Mahinda Thera and Ittiya Thera are deposited there also. Accordingly it is now a historical truth that Elder Mahinda visited this island in the 3rd century B.C. with four other Bhikkhus as his companions.
This fact is further confirmed by an inscription of Mahadathika Mahanaga at Mihintale. The names of Itthiya, Uttiya and Bhadrasala are mentioned therein with the name of Elder Mahinda.
In 1951, the base of the Stupa was completely cleared of debris. After this the interior of this monument was investigated. It led to the discovery of a relic casket of polished black earthenware of a type hitherto unknown either in Sri Lanka or India. The casket is cylindrical in shape, and is 5 3/8 ins. in height and 2 7/8 ins. in diameter at the base.
It is formed of three pieces, fitting one to the other, the uppermost to serve as the lid and the other two forming two separate compartments. This relic casket constitutes the most important specimen of ceramic art so far found in Sri Lanka. In the upper compartment of this casket was found a reliquary of thin gold foil.
It was 1 3/4 ins. in height and 1 9/16 ins. in diameter at the base made in the shape of a miniature Stupa of the oldest type known. The dome is bubble-shaped and above it is the cubical harmika surmounted by a single chattra or umbrella.
By the side of the umbrella shaft is shown the yupa projecting above the harmika. Inside the reliquary were found, in addition to beads and trinkets, minute fragments of bone and a small quantity of ash.
In the other compartment was found a miniature reliquary, in height 36 inches, in the shaper of a Stupa without chattra. In this too was found a small quantity of bone and ash.
The type of the Stupa is the same as that at Sanci. This form of the Stupa corresponds to the Stupas of the 3rd or 2nd century B.C.
Inside another relic chamber, which was added to this Dagaba at a later date, probably in the 7th or 8th century a guilt bronze image of the seated Buddha in the Dhyana-mudras was found.
Two other images of the seated Buddha made of thin gold foil and filled with paste were found at the floor of the relic chamber.
The style of the Buddha images and of the reliquary found in this chamber indicates that it had been made in this Stupa in two different periods, one separated from the other by about a millennium.