The post-pagan history of Ukraine begins in 988 AD, the year in which the Prince of Kyiv – Volodymyr the Great – adopted Christianity. It was Volodymyr who married the Byzantine Emperor’s sister in exchange for agreeing to support Byzantium militarily.
Volodymyr’s son, Yaroslav, built the Cathedral of St. Sophia in Kyiv, modeled after the Hagia Sophia in Constantinople, and married his daughters off to royal houses of European powers (Norway, Hungary and France), thus consolidating the power and prestige of the state of “Kyivan Rus” (or ‘Rus’). The word “Rus” became the root for two terms, “Ruthenia” and “Russia.” These terms began to assume distinct definitions in the 13th century, when the Mongol Invasion isolated Moscow from the West, and western Kyivan Rus maintained relations with western states.
Prince Yaroslav’s Code of Rus, the 1st law in the country, remained in force until the end of the 15th century. Yaroslav became “Yaroslav the Wise” in history. He expanded the borders of Kyivan Rus from the Baltic to the Black Seas and married his sister to the King of Poland, thus securing the border between Poland and Rus. He also married his son off to the daughter of the Byzantine Emperor Constantine Monomakh.
Constantine’s son, Volodymyr, became the ruler of Rus, the state that begat Russia, and Volodymyr Monomakh’s crown became the crown of all the Russian tsars. When Yaroslav died in 1054, he bequeathed his territories to each of his three sons, and a period of internecine strife and war ensued. In the midst of the chaos, Vikings captured Kyiv.
In 1147, Yuri Dolgorukii (youngest son of Volodymyr Monomakh) founded Moscow, which would become the nucleus of a new state north of Kyiv known as “Muscovy.” Kyivan Rus meanwhile became fragmented and divided into a dozen or so different principalities. As the Ruthenian Federation of Kyivan Rus began to disintegrate, the decline of Constantinople led to economic crisis, and trade and commercial ties with Byzantium receded. Eventually, in 1223, the Mongol Invasion defeated the joint forces of all the Rus princes, and in 1240, after a long and heroic defense, Kyiv surrendered to the “Golden Horde” of the Mongol Empire. This marked the end of Kyiv as a historic center uniting the eastern and western forces of Rus. Moscow became isolated from the West.
In 1246, Prince Danylo Romanovych of Halych-Volhynia, in the western part of Kyivan Rus, was forced to pledge allegiance to the Mongol khan. Danylo devoted his rule to ridding his domain of the Mongol yoke, and did succeed in gaining some independence from the Mongols. Pope Innocent IV eventually crowned him “Rex Rusiae” (King of All Rus) in 1253. Danylo founded both Halych and Lviv in honor of his son, Lev, and maintained Kyivan Rus traditions with a Western orientation. But his attempts to create an anti-Mongol coalition in Europe failed.
The first half of the 14th century witnessed the disintegration of the Golden Horde, the death of the last Halych princes (without heirs), and Poland’s seizure of most of the principality. Lithuanian princes supplanted those of Rus. By the end of the 15th century, Prince Dmitri Donskoy of Moscow had beaten the Golden Horde on the field of Kulikovo, and by the next century Grand Prince Ivan III (the Great) of Muscovy had thrown off the Mongol-Tatar yoke and married the daughter of the last Byzantine emperor. It was at this time that the people known as the “Cossacks” first gained the attention of prevailing great powers and states as a military and political force. As nomads, the Cossacks inhabited the steppes, the flat lands stretching from southern and eastern Ukraine eastward into today’s Russia, Kazakhstan and beyond. They were hunters and bandits, but they would become celebrated folk heroes for their frequent raids on Tatar convoys attempting to supply Ukrainian and Russian slaves to the Crimean Khanate and Ottoman Empire. For this, the Cossacks became associated with freedom and the resistance to slavery. The Cossacks were “freemen.”
Cossack interference with the Crimean slave trade ultimately came to the attention of the Grand Duke Alexander Jagiellon of Lithuania (later King of Poland) through complaints from the Crimean Khan. Grand Duke Alexander half-heartedly attempted to put a stop to the Cossacks, but at the same time must have understood that the “freemen” served as a buffer between his own domain and the Crimean Khanate. The khan’s complaints to the grand duke were mostly fruitless, and the Cossack raids on the Crimean Tatars continued.
The Grand Duke of Muscovy, Ivan IV, proclaimed himself “Tsar” (Caesar) in 1547, and the “Tsardom of Muscovy” began to be referred to in Muscovy as the “Tsardom of Russia,” a conscious reference to an assertion of dominion over all the lands of historic Rus. Ivan IV would go down in history as “Ivan the Terrible” for his cruelty and military aggression.
The land known as Ukraine would thereafter find itself in a regular state of tension with Muscovy – or “Russia” – to the north, and just as the Mongol Invasion had driven a wedge between Moscow and the western parts of Kyivan Rus, so the Dnieper River proved to be a political fault line exploited by Moscow to sow division within Ukraine as a whole.