The mausoleum of Sufi Shaykh Zayn al-Din Abu Bakr Taybadi (d.1389) is a freestanding structure incorporating a square dome chamber, a shallow entrance iwan, and a pair of two-story chambers. The dome chamber is concealed behind the soaring entrance iwan, which rises to a height greater than twice that of the flanking two-story chambers. The inclusion of these vaulted chambers creates an entrance facade that is unusual in freestanding buildings. Such an elevation resembles the qibla facade of a number of courtyard mosques, including the congregational mosques of Natanz and Yazd. A single story arcade describing a courtyard was constructed in front of the iwan at a later date. The entrance iwan is barrel-vaulted, without muqarnas. The entire façade is decorated with marble and faience revetment. An inscription band that frames the portal is assembled of carved terracotta segments against a blue tile background, and may have provided a model for similar epigraphy in the Blue Mosque of Tabriz (1465), since examples of fifteenth century terracotta inscription are very rare. An inscription identifies the calligrapher as the same responsible for the Mosque of Gawhar Shad at Herat and the madrasa at Khargird. All other exterior façades are undecorated, but the brickwork divides all surfaces into panels, indicating an intention that the building was to be seen from all sides. Above the rectangular exterior of the chamber, the dome, semi-domes and vaults are massed in narrow horizontal layers of brick.Within a low, square exterior, the dome chamber interior is cruciform, with symmetrical recesses on all sides. Recesses on the north and south walls contain doors that provide side access to the exterior. The mihrab is not oriented toward Mecca, but is located in the western recess, opposite the iwan. The interior of the chamber is painted white, but for a mosaic dado of faience and stone. The stone sections bear graffiti inscriptions of pilgrims dating back to the fifteenth century. The four recesses are vaulted with a semi-dome, the corners articulated with muqarnas. A complex vaulting scheme covers the chamber. Quarter-domes provide transition from each corner of the square plan, formed by four intersecting ribs above each vaulted recess. The space formed by the four ribs, between the quarter-domes, is further divided into three sections; a small central muqarnas dome flanked by faceted side sections. Creases divide the space above the ribs into an octagon, above which are sixteen small niches, and a further division by creases that segments the dome into 32 panels.Sources:Byron, Robert Byron. 1977. "Timurid Architecture". In A Survey of Persian Art. (Arthur Upham Pope and Phyllis Ackerman, eds.) Tehran: Soroush Press, 1119-1164.Golombek, Lisa and Donald Wilber. 1988. The Timurid Architecture of Iran and Turan. Princeton, New Jersey: Princeton University Press.O'Kane, Bernard. 1995. "Taybad, Turbat-i Jam and Timurid Vaulting". In Studies in Persian Art and Architecture. Cairo: The American University in Cairo Press.
