Cathedral of St. Virgin Mary (Sioni) was built on the edge of VI-VII centuries AD. This is the main Christian cathedral of Tbilisi. Due to pillage of invaders, the cathedral went through numerous changes. In 1226 the Shah of Khorezm, Jalal-ed-Din, conquered Tbilisi. On his order the dome of Sioni was removed and his throne placed instead. Sitting on this throne he viewed those Georgians who refused to abuse the icons of Our Savior and Virgin Mary which were carried from the church and placed on the Metekhi bridge. That day 100 000 Christians were beheaded. In 1522 Sioni cathedral was ravaged by Shah of Iran, Ismail.

In 1675 Bishop Elise Saginashvili on the order of king Rostom attached a small chapel to the building of Sioni from the southern side, and placed a new dome on the cathedral. In 1710 Vakhtang VI made an outer facing of the Cathedral with the tuff. During this restoration ornaments and carvings were applied which adorn the Cathedral today.

During the Russian rule Sioni again sustained changes. In the 50-ies of the XIX century Grigori Gagarin made new mural paintings. In 1867 Sioni cathedral again renewed its existence. The last refurbishment works were conducted in Sioni in 1983. The Church of Michael the Archangel was set up in the southern chapel, and in the northern chapel – the Church of Vakhtang Gorgasali. New cross was installed on the dome.

The Sioni cathedral has two belfries. The bell tower deep in the court to the north of the cathedral dates back to 1725. To the west of the cathedral, on the other side of the street three-level bell tower with a spire was built in 1812 and represents the first specimen of Russian classicism.