A book, An Excursion of the Soul is the most Persian encyclopedia, which was probably written until 8th H century in Iran. An author of the book prepared the consequences of his scientific provisions in this book until the end of his life. He produced an authentic and comprehensive collection that placed many sciences and a variety of old knowledge within it. In addition of having deep information in the field of old knowledge including medicine, astronomy, mineralogy, literature, learning of cities, mountains, rivers, and even learning of living being, creatures, and plants; The book of An Excursion of the Soul, has the lexical particular merits too. This book includes one introduction, three essays, and a conclusion which the lowest apparatuses represent its exact explanations: The introduction in Islam history and astronomy, longitude and latitude, and a division of the countries. The first essay elaborates mineralogy, phytology, and zoology; the second essay elucidates human being in a comprehensive meaning (anatomy, medicine, ethics, ethos, rascality, beliefs, and whatever associated with a human being); the third essay describes history and geography, and the conclusion demonstrates unearthly and supernatural subjects. The scientist's author of the book (Hamd-Allah bin Abu-Bakr bin Hamd-Allah Moustoufi Qazwini), writes his composition based on Persian and Arabic ancient sources. He sometimes utilizes oral information and cognizance which belong to scientists, religions, and heresies as well. Hamd-Allah Moustoufi is an Iranian bureaucracy lineage which his ancestors have constantly assigned as commissioners in several positions during previous sovereignties include: In martial and governmental positions and even bureau affairs. At the beginning of his adolescence, he has himself worked according to (a Pragmatic method), which means governmental services; also inscribed a comprehensive calculation of the countries and nations several times, and awhile had a position of (belongings' writer) in Baghdad too. Hamd-Allah Moustoufi is a renowned and assured man in an arena of Islamic era's history writing. In addition of the book, An Excursion of the Soul, he has written many other works that one of his most distinguished corpus called as (A Selected History), the most important sources of the Iranian history during the middle centuries. Hamd-Allah Moustoufi's mausoleum is located in Ghazwin city. The comprehensive context of An Excursion of the Soul is corrected by Mir Hashem Muhdath, is known as a contemporary corrector and researcher who corrected and investigated it completely and delicately. The book was published and broadcasted by Ardehal Safir Publication in 1396.

Ḥamdallāh Mustawfī Qazvīnī was a Persian historian, geographer and epic poet who was descended from a family of Arab origin. Mustawfi is the author of Nuzhat Al Qulub , Zafar-Nameh , and the Tarikh e Gozideh . His tomb is a structure with a blue turquoise conical dome, at Qazvin. Effect of Illkhanate rule In his works regarding the history of Tabriz, Mustawfi mentions that before the arrival of the Mongols the people of Tabriz spoke Pahalavi Persian and later began to speak Adhari Turkish during Illkhanate rule. He also mentions that the people of Maragha, Zanjan and Ardabil had their own Persian dialects.