On February 17, 1106 the holy prince, left his family and was tonsured at the Kiev Caves monastery. Nicholas Sviatosha carried out his obediences with great humility. For three years he worked in the kitchen, for which he chopped wood and carried water. For the next three years, he was gatekeeper at the monastery. The saint had a garden around his cell. Out of his own means he built at the monastery the temple of the Holy Trinity and the infirmary church in the name of St Nicholas, his patron saint.
St Nicholas was the first of the Russian princes to accept monasticism, patiently enduring the reproaches of his brothers for his decision to lead a life of humble obedience. The saint’s doctor, Peter, pointed out to the royal ascetic, that such exploits of obedience had injured his health. But suddenly the doctor himself fell sick, and was healed only by the prayer of St Nicholas. Then Peter himself was tonsured.
After he had progressed through various obediences, St Nicholas took upon himself the vow of silence. When the saint received money, he used it to beautify the church, and to procure books (because he loved reading), or he distributed it to the poor. St Nicholas was a zealous peacemaker, in 1142 he reconciled the Prince of Chernigov with the Great Prince Vsevolod.
Soon after the death of the saint, his brother Prince Izyaslav fell grievously ill. The igumen of the monastery sent the sick man the saint’s hairshirt. Izyaslav put it on and was healed.