During the 11th century, nomadic East Turkic people, known as the Polovtsi,* made frequent raids on Kiev. During one of these a certain Polovtsian was taken prisoner and kept in a man’s house in Kiev.
One day the jailer told the prisoner, “Pay the ransom and you may go free.” The man had no money, but they agreed that he could go and return with the ransom. Before leaving, they went together to the church for the prisoner to seal his promise by making an oath in front of Saint Nicholas’ icon.
On his way home, the Polovtsian laughed to think the naive jailer really thought he’d be paid! When he got home, the man’s family urged him to forget about the debt. So the Polovtsian ignored his oath and went about his daily life.
After some time passed, Saint Nicholas appeared to the man, urging him to pay the ransom. The Polovtsian continued to ignore his obligation. One day Saint Nicholas came again as the man was out riding his horse. The saint threw him to the ground, ordering him to honor his oath. But again, he did not.
Several days later, all the Polovtsian nobles and princes met and this man was among them. Nicholas came a third time. He threw the man to the ground and began to beat him. The others were terrified to see an invisible force throw their comrade down and beat him with invisible sticks.
The man’s family carried him home. After recovering, he explained what had happened. “Go and pay,” they said, afraid more misfortune would befall them. So the Polovtsian returned to Kiev, bringing two herds of horses. He went first to give the smaller herd to the church. Then he took the larger to the man who been his jailer, explaining all that had happened. The Kievian jailer was overjoyed and went to church to thank Saint Nicholas for the miracle repayment.
*The Polovtsi, also known as Cumans or Kumans, warred against the Byzantine Empire, Hungary, and Kiev for two centuries. Eastern Slavs defeated them in the early 12th century and when the Mongols came in 1245, many were taken as slaves and others went into exile.
The vitae of St. Nicholas and His Hagiographical Icons in Russia, Vol. 2 doctoral dissertation by Alexander Boguslawski, University of Kansas, 1980, pp. 88-89.