The stupa was enlarged on five occasions during the following centuries, every time by building over, and encapsulating, the previous structure.
The stupa was excavated by an Italian mission (IsIOAO: Istituto Italiano per l'Africa e l'Oriente), led by archaeologist Domenico Faccenna from 1956, to clarify the various steps of the construction and enlargements.
[1] An Indo-Corinthian capital representing a Buddhist devotee within foliage has been found which had a reliquary and a coin of Azes II buried at its base, securely dating the sculpture to earlier than 20 BCE.
The oldest core strata (GSt 1) revealed a coin of Chandragupta Maurya and is therefore dated to the Ashokan period.
[4] More conservative estimates date it to the 1st-2nd century CE, roughly at the same time the first known statues of the Buddha were made in the art of Mathura.