In letters to Nestorius which were afterwards included among the council documents, Cyril explained his doctrine. He noted that "the holy fathers... have ventured to call the holy Virgin "Theotokos", not as though the nature of the Word or his divinity received the beginning of their existence from the holy Virgin, but because from her was born his holy body, rationally endowed with a soul, with which the Word was united according to the hypostasis, and is said to have been begotten according to the flesh" (Cyril's second letter to Nestorius).