The Center organized a seminar in which Dr. Omar Maan al-Ali, lecturer at the faculty of Arts, delivered a lecture on "The Structure of the economic system of the Abbasid Caliphate". He discussed a number of topics related to the economy and trade system during the period under review. He began his lecture by a recapitulation of the history of agricultural sector and its positions during the Abbasid era and introduced the nature of ownership of private agricultural lands, for instance, agricultural land considered to be Kharāj land, and the Usher land upon whose fruits one tenth is due as Zakah. Moreover, he made a comparison between Kheraji and Usher lands. He also explained the conditions of arid land (mewat land) and the lands owned by the Ummah or the Public treasury (Bait-ul-Maal) in other words the lands belongs to the Caliph and the State. In his final talks about the land types he reviewed the importance of the waqf lands and feudalism system and the condition of big land lords. He also discussed the monetary system during the Abbasid era and pointed out that the Abbasid Caliphate introduced a number of dinar and dirham which were inscribed with simple Kufi style of writing. According to his research the weight of the Umayyad dirham ranged from 2.22 to 4.28 grams, while the weight of the Dinars fluctuated between 4.22 to 4.28 grams. The names of caliphs as well as the names of crown princess, ministers and commanders were inscribed on dirham and dinar. He also shed lights on the economic system of the Abbasid state saying that they were familiar with bills of exchange as well as Bayt al-mal system which has a number of functions but initially it served as a royal treasury for the caliphs and managing personal finances and government expenditures. According to him there was also a special kind of treasury house which served the group of interests who had been investing their whole or partial funds in banking activities such as borrowing and lending loans debts etc. He also talked about the trade activities during Abbasid period and reviewed the Baghdad market as an example. He tackled on circulated commodities and stuffs in the market places pointing out the measures system in the markets and trade relations between Baghdad and other countries such as China, India and Sind across the Arabian Gulf discussing the import and export system between those countries. In his conclusion he talked about the home industrial activities and position of the local craftsmen and their relations with the government's administration. He concluded that the Abbasid Caliphate was known for its unique and developed economic networks which the previous states were not familiar with especially in financial matters and banking services that were being run by a high level of political and economic management.