By the end of 1245, only Mikhail from among the three senior princes had not yet kowtowed to the conqueror.
In the end, Mikhail went in time to pre-empt a Mongol punitive strike against his domain; his grandson, Boris Vasilkovich of Rostov accompanied him.

When they arrived at Saray, Batu Khan sent messengers to Mikhail's camp instructing him to worship according to the laws of the Mongols by bowing to the fires and idols.
Mikhail agreed to bow to the khan, but he insulted the Mongol by refusing to obey his command to worship idols.
Enraged by the prince's retort, Batu Khan ordered that he be put to death.
He was slaughtered by Doman of Putivls, and Fedor his boyar was killed after him.
The Novgorod First Chronicle, the oldest chronicle reporting his death narrates that their bodies were thrown to the dogs; but as a sign of divine favor, their bodies remained unmolested and pillars of fire hovered over them.

(…) when Michael, one of the princes of Russia, came to submit to Bati, the Tartars first tried to make him pass between two fires.
After this they said that he should bow south to Chingis Khan, but he replied that he would gladly bow to Bati and his servants but not to the image of a dead man because this is improper for a Christian.
When he was repeatedly told through his son Yaroslav that he must bow, and yet he refused, Bati ordered Prince Michael killed if he would not bow.
Prince Michael of Chernigov was passed between fires in accordance with ancient Turco-Mongol tradition.
Batu Khan sent to stab him to death for his refusal to do obeisance to Chingis Khaan's shrine in the pagan ritual imposed by the conqueror.
The prince replied that he "preferred to die rather than do what was wrong".
Bati sent Michael to one of his followers who trampled on his chest with his boots until the prince died.
Meanwhile the prince comforted one of his soldiers who stood near by him by saying: 'Be strong because your punishment will not last long and then at once eternal joy will follow.'
After this his head was cut off quickly with a knife.
The soldier, to tell the truth, also had his head cut off with a knife.

— Giovanni DiPlano Carpini: The Story of the Mongols whom We Call the Tartars
The chronicle narrative accounts show that the people of Rus' acknowledged Mikhail and Fedor as martyrs immediately after their deaths.
Accordingly, their bodies were later brought to Chernihiv and entombed in a side-chapel dedicated to them (The Miracle-Workers of Chernigov) in the Holy Saviour Cathedral.

His wife survived him and promoted his cult.
His daughter Maria and her sons, Boris and Gleb Vasilkovich, inaugurated the Feast of the Miracle-Workers of Chernigov, on September 20, and built a church in their honor.
Her sister, Feodula who had become the nun Evfrosinia also advanced his cult to judge from a 17th-century account which reports the existence of a wooden chapel in Suzdal dedicated to them.

The cult was approved in 1547.
When Chernihiv was occupied by the Poles in 1578, Ivan IV the Terrible had the relics of the two saints taken to Moscow, where they were placed in the cathedral of Saint Michael the Archangel.
In times of oppressions particularly, these martyrs have been regarded by the Russians as their special representatives before God.
By the end of 1245, only Mikhail from among the three senior princes had not yet kowtowed to the conqueror. In the end, Mikhail went in time to pre-empt a Mongol punitive strike against his domain; his grandson, Boris Vasilkovich of Rostov accompanied him.
When they arrived at Saray, Batu Khan sent messengers to Mikhail's camp instructing him to worship according to the laws of the Mongols by bowing to the fires and idols. Mikhail agreed to bow to the khan, but he insulted the Mongol by refusing to obey his command to worship idols. Enraged by the prince's retort, Batu Khan ordered that he be put to death. He was slaughtered by Doman of Putivls, and Fedor his boyar was killed after him. The Novgorod First Chronicle, the oldest chronicle reporting his death narrates that their bodies were thrown to the dogs; but as a sign of divine favor, their bodies remained unmolested and pillars of fire hovered over them.
(…) when Michael, one of the princes of Russia, came to submit to Bati, the Tartars first tried to make him pass between two fires. After this they said that he should bow south to Chingis Khan, but he replied that he would gladly bow to Bati and his servants but not to the image of a dead man because this is improper for a Christian. When he was repeatedly told through his son Yaroslav that he must bow, and yet he refused, Bati ordered Prince Michael killed if he would not bow. Prince Michael of Chernigov was passed between fires in accordance with ancient Turco-Mongol tradition. Batu Khan sent to stab him to death for his refusal to do obeisance to Chingis Khaan's shrine in the pagan ritual imposed by the conqueror. The prince replied that he "preferred to die rather than do what was wrong". Bati sent Michael to one of his followers who trampled on his chest with his boots until the prince died. Meanwhile the prince comforted one of his soldiers who stood near by him by saying: 'Be strong because your punishment will not last long and then at once eternal joy will follow.' After this his head was cut off quickly with a knife. The soldier, to tell the truth, also had his head cut off with a knife.
— Giovanni DiPlano Carpini: The Story of the Mongols whom We Call the Tartars
The chronicle narrative accounts show that the people of Rus' acknowledged Mikhail and Fedor as martyrs immediately after their deaths. Accordingly, their bodies were later brought to Chernihiv and entombed in a side-chapel dedicated to them (The Miracle-Workers of Chernigov) in the Holy Saviour Cathedral.
His wife survived him and promoted his cult. His daughter Maria and her sons, Boris and Gleb Vasilkovich, inaugurated the Feast of the Miracle-Workers of Chernigov, on September 20, and built a church in their honor. Her sister, Feodula who had become the nun Evfrosinia also advanced his cult to judge from a 17th-century account which reports the existence of a wooden chapel in Suzdal dedicated to them.
The cult was approved in 1547. When Chernihiv was occupied by the Poles in 1578, Ivan IV the Terrible had the relics of the two saints taken to Moscow, where they were placed in the cathedral of Saint Michael the Archangel. In times of oppressions particularly, these martyrs have been regarded by the Russians as their special representatives before God.
Michael of Chernigov