Tornike Eristavi, a renowned Georgian military commander and favorite of King David Kuropalates, eventually renounced worldly glory to pursue a spiritual life. Seeking his spiritual father, Saint John, he journeyed first to Mt. Olympus, then to Mt. Athos, where he joined a monastery led by Saint Athanasius the Athonite. There he was tonsured a monk and given the name John.

As more Georgians came to Mt. Athos, John built a church dedicated to Saint John the Theologian and established the first Georgian monastic community there.

When Bardas Sclerus rebelled against the Byzantine emperors, Empress Theophania requested John-Tornike return to Georgia to seek military aid. Though reluctant, he obeyed after receiving a blessing. King David agreed to help, on the condition that John-Tornike lead the army. Under his command, twelve thousand Georgian troops defeated Bardas Sclerus around 979.

After the victory, John-Tornike returned to Mt. Athos, where he lived in humility and obedience. He never acted without a blessing and embraced silence in his later years, speaking only once more at the request of Saint John. He reposed peacefully, remembered as a model of faith and humility.