The development of Sīrah literature is closely linked with the transmission of the Ḥadīth and should be viewed in connection with it. The Sīrah aimed at giving information about the men who aided the Prophet loyally and faithfully, about stubborn opponents and enemies who persecuted him and those who later fought him, about hypocrites who concealed unbelief and hatred in their souls and about Companions who suffered and fought for him. A subject of considerable importance in the formation of Sīrah literature, comprehensively dealt with also in some commentaries on the Qur'ān, was the stock of stories about the creation of the world. The process of elaborating and enlarging upon the stories of the Qur'ān widened the scope of the Muslim conception of history. Genealogy was an essential subject of the Sīrah literature. Traditions stress the purity of the Prophet's pedigree and the qualities of his ancestors.