Temple 40 was built of octagonal stone columns of this hall that were erected in five rows of ten each, since many of the broken shafts of the columns were found in original position. It’s located in the South East of the Great Stupa and can be accessed from the Southern paved path as well as from the Temple 45 also, which is located on higher eastern area, accessed through a flight of steps.
According to the explorer Sir John Marshall it seems probable that the number of columns in the hall was considerably over fifty, the extra ones having formed one or more rows at the sides or ends of the existing structure.
Apart from the large octagonal pillars, there are several smaller pillars which are of about the same age i.e. 3rd century BCE, which are square at the bottom and octagonal at the top. These pillars may have been erected to support an open veranda surrounding the hall, or possibly they were employed in a supporting structure to the south.
The absence of architraves and capitals in the excavation debris indicates that the superstructure was entirely built of wood. The remains show that in about the seventh or eighth century AD, a temple with a portico and entrance facing west was built on the eastern side of the platform, and probably at this time the small square pillars were put in the position described above.
Before the Mauryan period it might have been used as a resting place or as a meditation place for the monks. This apisidal was intentionally burnt may be with the Great Stupa by the Ist Sunga ruler. Later Sunga dynasty ruler rebuilt the same, and during the Sunga period it was probably being used for ceremonies like Uposatha.
Temple 40, precisely can be described as, it was an arcuated roofed hall with a wooden super structure built in the third century BC. It was later burnt down and a pillared hall was built on its platform in the second century BC. Some additions and alterations were made to the structure around the seventh or eighth century AD. Remains of this structure are considered prior to Ashoka probably it was built by Bindusar.
It’s considered one of the important ruins, located within the Buddhist Monuments enclave, visited by tourists, students, researchers and Archaeologists.