The stupa, originally conceived as a funerary mound, symbolizes the entry into Nirvana and ultimate achievement of Buddhahood. It represents one of the primary objects of veneration for Buddhists and often functions as a reliquary.
The concept of the present stupa model encircled by figures is entirely unique in the context of Gandharan art, possibly serving as a traveling shrine, as the various parts can easily be assembled and dismantled. Indra and Brahma are frequently represented in Gandharan iconography and appear as witnesses at key scenes in Buddha's life, for example at his birth, when Indra receives the child Buddha born from the side of his mother Queen Maya and Brahma stands by respectfully. The forth figure alongside Maitreya is not clearly identifiable due to the lack of attributes.
Given the construction of this piece in various parts, some might be later additions or replacements, notably the central drum of the stupa and the forth figure of a donor. The inscription on the base reads: "[Gift of] Sivaraksitaka, the stupa with people around it paying homage." Remarkable in this Buddhist context is that the name of the donor literally means 'protected by Shiva'. The dating on paleographic grounds is no later than 150 AD.
For a model of a stupa sourrounded by four columns crested by lions, from the James and Marilynn Alsdorf Collection, see P. Pal, A collecting Odyssey, 1997, p. 76.