Saint Thomas Đào Đình Toán was born in 1764 in Cần Phán village, Thái Bình province. He served both as a member of the Dominican Third Order and as a trusted catechist in the evangelization efforts in Trung Linh.

On December 16, 1839, officials from Xuân Trường district sent soldiers to search Trung Linh village. Teacher Toán was arrested and ordered to trample on the Holy Cross—but he refused. He was then taken to Xuân Trường district headquarters.

During brutal torture, on January 19, 1840, he did step on the Holy Cross. However, seeing his hesitation and reluctance, Governor Trịnh Quang Khanh doubted the sincerity of his apostasy. The governor then ordered two men who had previously renounced the faith to beg him tearfully for help, threatening that they would be executed if he did not renounce Christianity himself. They even uttered blasphemous words against God. To prevent them from committing further sin, Teacher Toán once again stepped on the Holy Cross—though his heart was filled with profound sorrow. He later deeply repented and wept bitterly over this act.

Fifteen days afterward, Father Dominic Trạch was arrested and imprisoned together with him. The priest consoled and heard his confession, helping him regain spiritual strength.

When brought once more before Governor Trịnh Quang Khanh, Teacher Toán boldly professed his faith. Astonished, the governor ordered him severely beaten. As soldiers dragged him past the Holy Cross, he suddenly rose, knelt down to reverently kiss the image of the crucifix, and loudly recited the Act of Contrition prayer.

The governor then ordered his clothes stripped off, subjected him to renewed beatings, tied two crosses to his feet, exposed him to the scorching sun without food or water, and commanded everyone present to insult and revile him. Teacher Toán remained silent and endured everything without a single word of complaint.

When he became too weak from hunger, the officials offered him fine food and wine—but on the condition that he trample the Holy Cross. He firmly replied: “If eating requires me to renounce my faith, I will never eat.”

On June 27, 1840, Teacher Thomas Đào Đình Toán died in prison in Nam Định.

He was beatified on May 27, 1900, and canonized by Pope John Paul II on June 19, 1988.