Saint Telesporus died ca. 136 AD; he is included among the saints in the current Roman Martyrology; his feast is presently commemorated on January 2nd.
O GOD! who hast called forth Saint Telesphorus from the desert to the supreme government of Thy Church, and to the triumph of martyrdom; we beseech Thee to grant that, bearing all trials with a humble heart for the glory of Thy name, we may be enabled to win the palm of heavenly glory. Through our Lord Jesus Christ, Your Son Who lives and reigns with You in the unity of the Holy Spirit one God, forever and ever. Amen.
Telesphorus, a Greek, embraced the rule of the anchorites, and he was celebrated alike for the holiness of his life and for the bright light of his learning. After the fierce combats of solitude, he was raised to the sacred throne of the Supreme Pontiff amid the general applause, and there, as if placed on a candlestick, he spread about him the brightness of life and character which befitted his high dignity. Zealous in the strengthening of discipline in the Church, he passed various decrees, amongst which was one ordering that for seven whole weeks before Easter all clerics called to have part with the Lord should fast, and strive to cleave to God day and night, with hymns, prayers, and watchings. He said that as the life of clerics ought to differ from that of laymen, there should be a like difference in their fast, and that, since they were called the familiar friends of our Lord and Saviour, they should be men set apart by their character and by their holiness.
The fast of Lent, which had been appointed by the order of the Apostles, was differently observed in the various churches. Telesphorus, therefore, by a pontifical decree, established it forever on a firm basis, and he likewise decreed that every priest should say three Masses on the Nativity of our Lord: one at midnight, when Christ was born at Bethlehem; one at dawn, when He was adored in the manger by the shepherds, and one at the third hour, when the day of the Redemption broke upon us. He commanded, moreover, that the hymn of the angels, “Glory to God in the highest,” should be repeated in these Masses. He forbade Mass to be celebrated, at other times, before the third hour, at which time we read that Christ was crucified, and that the Holy Ghost came down upon the Apostles.
This watchful shepherd was not content with guarding himself the fold intrusted to him, and putting down the false teachings of heretics by his preaching and writings, but for this purpose he made use of priests who were remarkable for piety and learning, and these he sent to the different parts of the earth. He checked the heresy of Valentinus, who taught that Christ our Saviour was born of the Blessed Virgin in such a way that He took no flesh of her, but that, clothed with heavenly flesh, He merely passed through her breast as through a channel. He put down also the heresy of Marcion, who maintained that there were two Gods, one good, and the other bad, and who denied the resurrection of the body. While Telesphorus was applying himself most fervently to the preaching and spreading of the faith, he was seized by a riotous mob of heathen, accompanied by the priests of their idols, to whom he was an object of hate. His head was cut off, and he gained thereby the palm of martyrdom. He was buried near the body of Saint Peter in the Vatican, after having reigned eleven years eight months and twenty-seven days. He held four ordinations, in which he made twelve priests, eight deacons, and thirteen bishops for different places.
Taken from the book “Saints of Carmel” (BOSTON: JOHN CASHMAN & CO., 1896).