Three domed square mausolea stand along the north-south axis in Ozgön or Uzgen, which became the second capital of the Qarakhanid Dynasty in the eleventh century. Situated on the Silk Route between Kashgar and Tashkent, the city was an important trade center by virtue of its control of the narrow passage through the Kara-Darya Valley. These mausolea are of the few early Islamic structures that survived Genghis Khan's pillage of Transoxiana in the thirteenth century and illustrate the significant period development in Islamic decoration.
The three mausolea, popularly referred to as the northern, middle and southern mausolea, have square plans with imposing west-facing portals. The largest middle mausoleum was the first one built in 1012-13 for Qarakhanid ruler Nasr ibn Ali (996-1013). The northern mausoleum, believed to be dedicated to Jalal al-Dunya wa'l-Din Husayn (1132-56), a successor of Genghis Khan, was constructed in 1152-53. The southern and smallest mausoleum was built in 1186; its occupant is not known. The structures are all built of fired brick and feature a rich decorative scheme composed of carved brickwork, terracotta tiles and ornaments in alabaster.
The middle mausoleum is almost as wide as it is tall, measuring eleven and half meters by side on the exterior. Largely ruined, the central room has doorways on three sides and a niche on the fourth. The emphasis on the front portal was new at the time; it is achieved with a profusion of ornament with geometrical and vegetal motifs in carved alabaster. The doorway niche is framed by a lancet arch supported on engaged colonnettes and framed with decorative bands. The façade displays early versions of arabesque patterns known as girikh, while carved plaques and inscriptive friezes inside the room feature some pre-Islamic motifs.
The northern mausoleum, which is 10.2 by 12.2 meters on the exterior, is one of the best surviving specimens of early Islamic art. The attention to the entry façade is continued with incised terracotta motifs on flanking columns, inside the portico and on the soffit of the portal arch. The portal's framing colonnettes are surfaced with a rhomboidal brick pattern while the archivolt of the entry arch features Naskhi script, with plaited Kufic inscriptions defining the lintel course.
The southern and most ornately decorated mausoleum measures 6.4 meters per side on the interior. Its portal contains Naskhi and Kufic inscriptive panels combined with stars, crosses and floral motifs (islimi) including a winding grape vine motif. Once referred to as the encyclopedia of eleventh century ornaments in Central Asia, the mausolea have become national symbols of the Kyrgyz Republic and are featured on banknotes.