Lawrence of Portugal
A letter survives in the Register of Innocent IV, dating Lawrence's departure from Lyon to 5 March 1245. The letter, published in Monumenta Germaniae Historica and usually referred to as Dei patris immensa, suggests that his mission was primarily religious in character. Lawrence was to have approached the Mongols from the Levant. Nothing is known of his fate, and the possibility remains that he never left.
- Monumenta Germaniae Historica; Epistolae Saeculi XIII: E Regestis Pontificum Romanorum, ed. Karl Rodenberg (Berlin, 1887), Vol. 2, No. 102, p. 72. 
- Igor de Rachewiltz, Papal Envoys to the Great Khans (Stanford University Press, 1971), p. 87.
- Gregory G. Guzman, "Simon of Saint-Quentin and the Dominican Mission to the Mongol Baiju: A Reappraisal" Speculum, Vol. 46, No. 2. (April., 1971), p. 234.