Born at Rocca Secca in the Kingdom of Naples, 1225 or 1227; died at Fossa Nuova, March, 7, 1274.

      Landulph, his father, was Count of Aquino; Theodora, his mother, Countess of Teano. His family was related to the Emperors Henry VI and Frederick II, and to the Kings of Aragon, Castile, and France. Calo relates that a holy hermit foretold his career, saying to Theodora before his birth: "He will enter the Order of Friars Preachers, and so great will be his learning and sanctity that in his day no one will be found to equal him" (Prümmer, op. cit., 18). At the age of five, according to the custom of the times, he was sent to receive his first training from the Benedictine monks of Monte Cassino. Diligent in study, he was thus early noted as being meditative and devoted to prayer, and his preceptor was surprised at hearing the child ask frequently: "What is God?"

      Some time between 1240 and August, 1243, he received the habit of the Order of St. Dominic, being attracted and directed by John of St. Julian, a noted preacher of the convent of Naples. The city wondered that such a noble young man should don the garb of poor friar. His mother, with mingled feelings of joy and sorrow, hastened to Naples to see her son. The Dominicans, fearing she would take him away, sent him to Rome, his ultimate destination being Paris or Cologne. At the instance of Theodora, Thomas's brothers, who were soldiers under the Emperor Frederick, captured the novice near the town of Aquapendente and confined him in the fortress of San Giovanni at Rocca Secca. Here he was detained nearly two years, his parents, brothers, and sisters endeavouring by various means to destroy his vocation.

      The time spent in captivity was not lost. His mother relented somewhat, after the first burst of anger and grief; the Dominicans were allowed to provide him with new habits, and through the kind offices of his sister he procured some books -- the Holy Scriptures, Aristotle's Metaphysics, and the "Sentences" of Peter Lombard. After eighteen months or two years spent in prison, either because his mother saw that the hermit's prophecy would eventually be fulfilled or because his brothers feared the threats of Innocent IV and Frederick II, he was set at liberty, being lowered in a basket into the arms of the Dominicans, who were delighted to find that during his captivity "he had made as much progress as if he had been in a studium generale" (Calo, op. cit., 24).

      Thomas immediately pronounced his vows, and his superiors sent him to Rome. Innocent IV examined closely into his motives in joining the Friars Preachers, dismissed him with a blessing, and forbade any further interference with his vocation. John the Teutonic, fourth master general of the order, took the young student to Paris and, according to the majority of the saint's biographers, to Cologne, where he arrived in 1244 or 1245, and was placed under Albertus Magnus, the most renowned professor of the order.

      In the year 1251 or 1252 the master general of the order, by the advice of Albertus Magnus and Hugo a S. Charo (Hugh of St. Cher), sent Thomas to fill the office of Bachelor (sub-regent) in the Dominican studium at Paris. This appointment may be regarded as the beginning of his public career, for his teaching soon attracted the attention both of the professors and of the students. His duties consisted principally in explaining the "Sentences" of Peter Lombard, and his commentaries on that text-book of theology furnished the materials and, in great part, the plan for his chief work, the "Summa theologica."