Ferdinand I of Aragon vs Vladimir the Great

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.

Vladimir converted to Christianity and married Anna, sister of Byzantine Emperor Basil II, after capturing Chersonesus. He was baptized in Chersonesus, adopting the name Basil, and initiated the Christianization of Kievan Rus.

Vladimir ordered the mass baptism of the people of Kiev in the Dnieper River. Pagan idols were destroyed, and churches were built. This event established Christianity as the state religion of Kievan Rus.

Vladimir led a military campaign against the White Croats in the Carpathian region, expanding Kievan Rus' territory westward. This campaign secured control over important trade routes and tributary tribes.

Vladimir built the Church of the Tithes (Desyatynna Church) in Kiev, the first stone church in Kievan Rus. He dedicated a tenth of his income to its maintenance, symbolizing the institutionalization of Christianity.