The article deals with the scientific environment of the Arab Caliphate in the ninth century, especially the history of this period. Ahmad al-Baladhuri was also one of the most influential scholars of the century, who worked in the fields of history and literature. In the article, historians who gave information about the life of Ahmad ibn Yahya al-Baladhuri, their works, the origin of the al-Baladhuri ratio, the conclusions of historians and researchers about it, the scholars of the Middle Ages with the same nisbah, Ahmad al-Baladhuri’s scholarly activities in Baghdad, his teachers and students, the historian’s trip to Damascus while seeking knowledge, his teachers there, and then his return to Baghdad, and his work as a nadim in the caliph’s palace. There is also information about al-Baladhuri’s scholarly activity, his works such as «Futuh al-Buldan», «Ansab al-ashraf», «Ahdu Ardasher». The date of Ahmad al-Baladhuri’s birth, his journey to Damascus, and his return from there were not specified in the sources studied, so a comparative analysis was made and an approximate date was recorded. Special emphasis was placed on Futuh al-Buldan and Ansab al-Ashraf, which have been preserved to the present day and have been published in modern editions. The article discusses the components of their subject, their study by Western and Eastern scholars, and their manuscripts, publications and translations.