The main church, set in a two-nave basilican plan, is a two-storey composite building, extensively altered, rebuilt, and enlarged in the course of history. The earliest construction phase, probably preceded by an earlier, 6th–7th-century shrine, is indicated by courses of brickwork in two crypts and refectory as well as a stone stela, with a carved stylized cross, built into a doorway under the sanctuary. The upper floor is an elongated, internally cruciform hall. The ground floor has a porch on the south. A bell tower—with nine arched, parallel-sided apertures—forms an addition to the porch, which was enlarged for this purpose in the 14th or 15th century. The south façade of this structure contains a tripartite composition, in which two arches, supported on an octagonal column, form an entrance, topped by a third arch. A small chapel and scriptorium annexed to the church on the south and west, respectively, were built in the 12th or 13th century, when the church appears to have been significantly enlarged and converted into a lavra. The church is notable for a Byzantine wall mosaic with the depiction of the Mother of God—surviving as a concentration of loose mosaic tesserae—a rare church adornment for the Georgian art, with only three other instances known at Tsromi, Gelati, and Martvili. The church bears several medieval Georgian inscriptions. One, on the south façade, makes mention of the chief mason Nikoloz; another commemorates the catholicos Mikel.