Ferdinand I of Aragon vs Igor of Kiev

Ferdinand I was elected King of Aragon by the Compromise of Caspe, a commission of nine representatives from Aragon, Catalonia, and Valencia. This resolved the succession crisis following the death of Martin I without a direct heir, bringing the Trastamara dynasty to the Aragonese throne.

Ferdinand I launched a military campaign to subdue the rebellious Sardinian nobles who had resisted Aragonese rule. The campaign successfully reasserted Aragonese control over the island, consolidating the Crown of Aragon's Mediterranean possessions.

Ferdinand I implemented administrative reforms in the Crown of Aragon, including the reorganization of the royal council and the standardization of tax collection. These reforms strengthened royal authority and improved the efficiency of governance across the diverse territories of Aragon.

Igor launched a naval attack on Constantinople. The Byzantine fleet, using Greek fire, destroyed most of Igor's ships. The campaign failed, forcing Igor to retreat and later negotiate a less favorable treaty in 944.

Following his failed campaign, Igor signed a treaty with the Byzantine Empire. The treaty renewed trade relations but imposed restrictions on Rus merchants and required Igor to provide military assistance to Byzantium.

Igor attempted to collect excessive tribute from the Drevlians, an East Slavic tribe. The Drevlians rebelled, captured Igor, and killed him by tying him to bent trees that tore his body apart. His death triggered Olga's revenge.