The “Summa theologica” had been completed only as far as the ninetieth question of the third part (De partibus poenitentiae). Thomas began his immediate preparation for death. Gregory X, having convoked a general council, to open at Lyons on May 1, 1274, invited St. Thomas and St. Bonaventure to take part in the deliberations, commanding the former to bring to the council his treatise “Contra errores Graecorum” (Against the Errors of the Greeks). He tried to obey, setting out on foot in January, 1274, but strength failed him; he fell to the ground near Terracina, whence he was conducted to the Castle of Maienza, the home of his niece the Countess Francesca Ceccano. The Cistercian monks of Fossa Nuova pressed him to accept their hospitality, and he was conveyed to their monastery, on entering which he whispered to his companion: “This is my rest for ever and ever: here will I dwell, for I have chosen it” (Ps. cxxxi, 14) . When Father Reginald urged him to remain at the castle, the saint replied: “If the Lord wishes to take me away, it is better that I be found in a religious house than in the dwelling of a lay person.” The Cistercians were so kind and attentive that Thomas’s humility was alarmed. “Whence comes this honor”, he exclaimed, “that servants of God should carry wood for my fire!” At the urgent request of the monks he dictated a brief commentary on the Canticle of Canticles.