The first volume comprises five books which principally treat of the creation of the world and the origin of the peoples who occupied New Spain (I, II), as well as the diverse nations constituting the Aztec Empire (III), followed by its conquest by the Spanish (IV) and its subsequent re-organisation (V). To the second volume were assigned nine books which deal with the religion (VI-X), government (XI), laws (XII), institutions (XIII) and social and military life of the indigenous peoples together with remarks on various geographical features and their cultural relevance (XIV). The subject of the seven books which constitute the third volume is the evangelisation of the Indians, with particular focus (especially in the last three books) upon the life, work and fate of Franciscan missionaries.