Located on the outskirts of the village are two clusters of structures that were perhaps originally joined as one group. The flanged tomb tower dedicated to the infant son of Oljaytu, and the congregational mosque to which it is attached, comprise the smaller grouping of structures in Bistam, just south of the larger shrine complex.

The exterior is articulated with 25 flanges and the interior is a decagon. A staircase runs between the walls of the outer flanges and the inner facets. The tomb is sited directly behind the qibla wall of the mosque, directly before all who prayed there. Blair and Bloom note that siting a tomb in this way was 'a new development that may also be seen in Mamluk architecture'. The tomb is entered from the interior of the mosque through an entrance passage that flanks the mihrab.

The flanges of the tomb tower bear comparison to the earlier flanged tower of 'Ala ad-din at Varamin (688/1289), which is in better condition, and which in turn is modeled after the tower of Rayy (534/1140). The flanges terminate with two encircling bands of blue faience Kufic inscription on a background of carved stucco. Remains of these inscriptions identify Muhammad ibn al-Husayn, the engineer and stucco-worker responsible for much of the two groups of structures at Bistam.

Sources:

Blair, Sheila S. and Jonathan M. Bloom. The Art and Architecture of Islam. New Haven: Yale University Press, 1994.

Pope, Arthur Upham. "The Fourteenth Century." In A Survey of Persian Art from Prehistoric Times to the Present, edited by Arthur Upham Pope and Phyllis Ackerman, Architecture, Its Ornament, City Plans, Gardens, Vol. 3, 3rd ed., 1052-1102. Tehran: Soroush Press, 1977.

Wilber, Donald N. The Architecture of Islamic Iran: The Il-Khanid Period. New York: Greenwood Press, 1969.