This research examines the copper coins, known as "Fulus," minted by Prince Yazid bin Asid al-Sulami at the Armenian mint during the Abbasid era. Prince Yazid bin Asid al-Sulami minted these copper coins during the reign of Caliph Abu Jaafar al-Mansur at the mints of Armenia and Bardha'a, during the reign of Caliph Muhammad al-Mahdi at the mints of Bardha'a and Dabil, and during the reign of Caliph Harun al-Rashid at the Haruniyya mint. This study will explore these copper coins issued during the reigns of these three caliphs in chronological order, from the earliest to the latest, and classify the available specimens into types. Each type will be studied individually, detailing its general form, inscriptions, and decorative elements that distinguish it from others, The research will be conducted in light of the information provided by historical sources such as Ibn al-Athir, al-Tabari, al-Baladhuri, and al-Ya'qubi, while acknowledging that these references are brief and sometimes contradictory.The significance of these copper coins lies in their accurate reflection of the historical events during the reign of Prince Yazid, encompassing the political, religious, economic, and social conditions of the state under which they were minted. They also shed light on new information not mentioned in historical sources, For instance, the Fulus that have reached us confirm that Prince Yazid bin Asid minted coins at the Armenian mints during the reigns of Caliphs Muhammad al-Mahdi and Harun al-Rashid. However, historical sources do not mention that Prince Yazid bin Asid governed Armenia during the reigns of these two caliphs. Thus, these coins reveal new historical facts and information not previously documented in the mentioned sources,Additionally, this research will study Twenty-nine coins that have not been previously examined by researchers. These coins will be analyzed and studied for the first time in this research. Furthermore, a Fals from the private collection of Mr. Abdullah al-Ajmi in Qatar will be published for the first time in this study. Therefore, this topic is of great importance in the field of Islamic numismatics and has not been previously addressed by researchers in a specialized study.