Rupban Mura an important archaeological site of mainamati lying on a hillock just between the modern BARD and BDR establishments in the Kotbari area on the south of the Comilla-Kalirbazar road. Excavations have revealed here the remains of a remarkable semi-cruciform shrine of medium size (28.2m east - west, 28m north - south), together with a number of subsidiary structures, including an octagonal stupa and another one on a square base. A boundary wall within the oblong stupa courtyard encloses all these. Its regular entrance is on the east, facing the monastery entrance. Deep diggings have revealed three main periods of building and repairs and rebuilding, the earliest corresponding to c.6th-7th centuries AD. Very few remains of the latest period (10th-11th century AD) survive now in this very heavily disturbed site.
The Cruciform Shrine Originally built as a solid stupa on a square base, it was subsequently converted into a semi-cruciform shrine in the second period (8th century AD). It has a peculiarity not noticed elsewhere. Instead of a single chapel built in each of the long arm of the cross, a group of three long narrow chapels was built in the eastern (front) side of the shrine.
In the middle chapel the colossal stone Buddha, now exhibited in Mainamati Museum, was discovered. The same peculiarity is noticed in the adjacent Itakhola Mura grand stupa, also on the eastern side facing the entrance. Fragments of bronze images found in other chapels suggest installation of such images there
The Monastery The small 34.1m square monastery of the site was built separately, 31m. south-east of the cruciform stupa. It has a prominent gateway complex (12.5m x 6.9m) projecting outwards in the middle of the northern wing. Built in the usual square plan, it originally had a total of 24 cells in four wings, subsequently reduced to 18 in the second period. The southern wing, occupying an area of 11.7m, was abandoned, due certainly to irreparable damages, and a row of new cells was built in its front, thus making the shape of the monastery oblong (34.1m x 24.8m). Corbelled niches and brick-built bedsteads can be noticed in the 2nd period cells. A broad corbelled drain was built in the courtyard to drain out rainwater.
Significant discoveries from the site include, besides the colossal stone Buddha, five debased gold coins of Balabhatta, the Khadga ruler.