In 1267, he published at Bologna a work on the duties of kings, but his task was interrupted in the same year by the death of his royal pupil, Hugo II., king of Cyprus.
Jean de Verceil had just sent to Thomas a famous tract in which the efficaciousness of the sacrament of penance was denied. He refuted it in a treatise called "De forma Absolutionis," with so much force and clearness that the Council of Trent adopted his very words in framing their canon.
About this time he was one day walking in the cloister of the convent at Bologna, plunged in deep meditation, when a lay brother, who did not know him, came up to him and said that he was obliged to go out on some matters of business, and that the superior had given him leave to take with him the first religious he met. S. Thomas, without excusing himself on the score of lameness from which he was then suffering, or of more serious engagements, went cheerfully with the lay brother; but the latter walked so fast, that Thomas was often left behind. But he was soon recognised, and the escort of citizens who respectfully followed the saint, opened the eyes of the lay brother. When they returned to the convent, the lay brother threw himself at the feet of Thomas and begged his pardon. Thomas raised him from the ground, saying, "It is not your duty, but mine to make an apology; for I ought to have remembered that my sore leg would not let me walk as fast as you wanted."
In 1269, Thomas was summoned to Paris, as "definitor" of the Roman province, to attend the general chapter of his order. S. Thomas prolonged his last sojourn in Paris for a year after the departure of S. Louis on his ill-fated crusade, in 1270, and during the whole time he continued to lecture, and to write his Summa.
S. Thomas was recalled to Bologna by his superiors early in 1271. Shortly after his return thither, he brought the second part of his Summa to a conclusion.
At the beginning of the year 1272, the chapter general of the order received requests from nearly all the universities of Europe that S. Thomas might lecture in them. The decision was in favour of Naples, for which he started at once. He visited Rome on his way, and there he began the last part of the Summa, and wrote his commentaries on several books of Boetius. Whilst he was explaining that book which treats of the Trinity, the candle which he held to light him, burnt down between his fingers, and scorched them severely, before his attention was aroused from his work.
After leaving Rome, Thomas and his inseparable friend Rainald were entertained at the villa of Cardinal Richard, where the two Rabbis were converted. Here Thomas fell ill, but the attack was slight, and quickly passed away.
In spite of all the precautions of Christian humility, his entry into Naples was a triumph. All classes, the lettered and the unlettered, the great and the small, hurried to welcome him. An excited yet respectful crowd accompanied him as far as the gates of that Dominican convent, where he had embraced religion. What would Theodora have said if she had seen her son entering in triumph that same house which she had regarded as the tomb of his glory?
The king, Charles I., assigned him a monthly pension, rather as a token of his royal favour, than as a reward for his services. The pilgrim who visits the Dominican convent at Naples, sees at the entrance of the great hall a representation of S. Thomas, and beneath it an inscription, "Before thou enterest, venerate this image and this chair, from which Thomas Aquinas uttered his oracles to a large number of disciples for the glory and felicity of his age."
The cardinal-legate of the holy see, wished to have an interview with our saint, and invited the archbishop of Capua, an old pupil of S. Thomas, to accompany him. The saint on being told of their arrival, went down into the cloister, but happening to be absorbed in thought, he forgot the object for which he had been summoned, and gravely continued his walk without taking any notice of them. The cardinal was offended, but the archbishop explained the cause of the saint's apparent rudeness. When Thomas woke from his reverie, he apologised, laying the blame on his feebleness of mind, which had not allowed him to find the solution of a theological difficulty without trouble and delay. The cardinal-legate withdrew, not knowing which to admire most, the learning, or the humility, of the doctor.