Tikhon of Kaluga was a Russian abbot and saint. He grew up in Moscow

Moscow

Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...

 and became a monk as a young man. He then moved to a forest near Medin in Kaluga

Kaluga

Kaluga is a city and the administrative center of Kaluga Oblast, Russia, located on the Oka River southwest of Moscow. Population: It is served by Grabtsevo Airport.-History:...

, living in the hollow of an oak tree. It was on that spot that he founded (and became the first abbot of) a monastery, dedicated to the Dormition of the Mother of God (and then to Tikhon himself after his death).