The most southerly of three tomb towers located in the Bagh-i Gunbad-i Sabz (Garden of the Green Gunbad) in Qum, this shrine (imamzada) belongs to Khwaja Asil al-Din and his uncle, two sheikhs of the influential Safi order that dominated Qum in the early fourteenth century. Known also as Jamal al-Din Ali, Khwaja Asil al-Din was the first member of the Safi family to gain political authority in the city of Qum and ruled until his death in 1357 (759 A.H.). Built in 1359 (761 A.H.), the tomb is adjoined by Gunbad-i Sabz (undated) and the Mausoleum of Khwaja Imad al-Din (1390).
The tomb is dodecagonal in plan with a double dome. Neither of the original domes has survived, and only in recent renovations the inner dome was rebuilt. The outer dome was most probably a polyhedral cone, similar to the surviving domes of the two adjacent structures. The entry to the tomb faces west and is accessed by three steps. An inscriptive medallion above the doorway contains the name of the architect, Hasan bin Alav (?) Khal'u, and the date of construction. The original entrance was probably to the north, where there is a low niche.
The exterior of the tomb is unadorned, except for arched niches carved into the facades. Every other niche has a window. There are two inscriptive plaques on the two south-facing façades; they contain the name of Ali, whose letters are formed simply by layering the bricks. The simplicity of the brick application marks a departure from the architecture of earlier Seljuk tomb towers where brick was cut and molded to form decorative details.
Inside, the tomb is eight-sided, with deep arched niches carved into each side. A sixteen-sided drum provides the transition to the dome; it also has arched niches on each side, of which four were pierced to allow light. Kufic inscriptions carved in plaster outline the lower niches, and each spandrel has an epigraphic medallion with Quranic mantras written in thuluth style. The name of the craftsman, Ali bin Muhammad ibn (or bin Abu) Shuja Ban'na, is found on two inscriptive plaques placed in the spandrels of arches on the northern wall. He is also known for the stuccowork at Gunbad-i Khadije Khatun (b.1360), Mazar-i Seiyyed sar Bakhsh (b.1364) and Imamzade Ahmad ibn Qasem (b.1308 or 1380) in Qum. Two inscriptive bands, executed in bold thuluth style, wrap the interior below and above the drum. The lower inscription gives the names of the two sheikhs buried in the tomb and the date of construction, 761, in Arabic numerals.
Pope, Arthur Upham, ed., Phyllis Ackerman, assist. ed. A Survey of Persian Art from Prehistoric Times to the Present. Vol. 3, Architecture, Its Ornament, City Plans, Gardens, 3rd ed. Tehran: Soroush Press, 1977.