This work was sent by the pope at once to Michael, emperor of Constantinople, as a message of peace. He had just returned to his capital, which Latin princes had held for more than half a century. The object of all his efforts was to reconstitute the power of the empire. To this task he brought an energy, a perseverance, and talents hitherto unknown among the sovereigns of that nation. He turned his eyes for help towards the pope; but it was the politician, rather than the Christian, that solicited the re-establishment of Catholic unity. S. Thomas, at the request of an Eastern prince, wrote a treatise in refutation of the errors that were rife in that part of the world. Nothing could be more modest than the way in which he stated his purpose, nothing more grand than the way in which he worked it out. Urban wished to reward his distinguished services. The great wealth he offered, the saint directed should be given to the poor. He declined the offer of the patriarchate of Jerusalem, and, shortly after, the honour of a cardinal's hat, for Thomas had thoroughly realized both the mysterious treasures of voluntary poverty and the hidden force of evangelical humility. The pope, finding he could not attach our saint to his court by the ties of honours or riches, bade him lecture at the various places where he took up his abode, Viterbo, Orvieto, Perugia, Fondi. Everywhere a prodigious number of pupils pressed around his chair. The churches were too small to receive the numbers who flocked to hear him. Historians only record one course of Lent sermons preached by him in Rome. One Christmas-eve he held a disputation with two Jewish Rabbis at the villa of a cardinal. After asking them to return in the morning, he passed the whole night in meditation and prayer. The Rabbis returned in the morning, but it was to ask for baptism. In 1263, Thomas was sent to the Dominican general chapter, held in London, as "definitor," in the name of the Roman province. Soon after his return to Italy, S. Thomas proposed to Urban the institution of a special festival throughout the Catholic Church in honour of the Holy Sacrament. When Urban was archdeacon of Liége, in the convent of Mont Cornillon, near one of the gates of the city, a poor religious named Juliana (April 3rd), as she prayed had a vision of the moon shining in all its splendour, but disfigured by one little breach. She desired to know its meaning, and an inner voice told her it was the Church, and that the breach represented the defect of a festival in honour of the Blessed Sacrament. After a time, an office in honour of the Blessed Sacrament was drawn up by a young religious. Robert de Torote, bishop of Liége, in 1246, appointed Thursday, in the octave of Trinity, for this feast.