According to historical sources, the first stone church on this site was built during the declaration of Christianity as the state religion in the 330s AD. According to Leonti Mroveli, John, a bishop sent by Constantine the Great to King Mirian with holy relics and abundant treasures to build churches in Georgia, stayed in Manglisi before proceeding to Mtskheta. He began constructing the church here and left a fragment of the Holy Cross of Christ. In the 7th century, Manglisi was ravaged during the invasion of Byzantine Emperor Heraclius, and the sacred relics kept here were taken away. During the reign of King George I (1014–1027), the architecture of the church underwent significant changes. Manglisi Sioni experienced its final major alterations in the mid-19th century.

Did you know that...

1. Among churches of this type, Manglisi Sioni is one of the earliest examples; therefore, its architectural details serve as a kind of reference point for the development of this style of architecture in Georgia.

2. In the mid-19th century, when restoration and repairs began on the church, which had been damaged first by attacks from the Lezgians and later by the campaign of Agha Mohammad Khan, many important architectural details were lost forever, and the interior frescoes were destroyed.