Sioni is an early example of a "four-apse church with four niches"[1] domed tetraconch (between the four apses are three-quarter cylindrical niches which are open to the central space). The church's cruciform interior measures 24m x 19.22m, and its façades are faced with carved rectangular greenish-gray stones, richly decorated with ornaments and figurative reliefs. The church is not dated but is very similar in design to the Jvari Monastery at Mtskheta, which is generally held to have preceded it, and, hence, has been described by some art historians as belonging to the "Jvari-type" group of churches.[2] Todosak, mentioned in an undated Armenian inscription on the southern facade as "I, Todosak, the builder of this holy church" is considered to have been an Armenian architect of the original church[3] or its late 10th-century renovator.[4]