The destruction of the Ostrogothic Kingdom of King Ermanaric in 370 CE (in modern day Ukraine) by the ferocious and nomadic Huns under Atilla’s grandfather (or greatuncle) was one of the seminal events of the first millennium, and second only to the founding of Christianity in the 1st Century CE. The ripples of the the Ostrogothic Kingdom’s destruction completely tore apart the fabric of social order in Europe, initiating the so-called “Dark Ages”. For nearly fifty years prior, the Hunnic horse archers raided Germanic, Gothic, and Slavic settlements and were unstoppable versus the infantry based armies of those nations. King Ermanaric’s suicide due to his impotence against the Huns, the first non Indo European steppe culture to move west, was a signal that the latest incursions were permanent and not mere raiding parties. “The Great Migration” westward began out of fear of the Huns.
For the next 100 years, the Huns so terrified the Germanic tribes that they fled westward and southwards. The Visigoths, Bulgars and Avars moved south into the corrupt and beset Eastern Roman Empire. The Angles, Saxons, and Jutes took to their boats and invaded the Romano-Celtic Island of Britain. The Alans, Burgundians, Alemanni, Vandals, Ostrogoths, Suebi, Langobards, Friisi, and Franks invaded the dying and dilapidated Western Roman Empire. Into the vacuum of Eastern Europe left behind by the Germanic tribes, moved not the Huns, but the Slavs.
The Slavs were primarily an agricultural people that lived from the Volga in the East to the Danube in the West. They formed the slaves, lower classes, and levies of the Hunnic, Germanic, and Gothic kingdoms in which they served, with a few independent but isolated tribal groups. As the Vandals, Burgundians, and Goths migrated from the fertile river basins of the North German Plain, they were replaced by the Sclavian Slavs, specifically the Wend, Sorb, Polans and Vistula tribes, with many refugees from the now defunct kingdoms displaced by the Huns. In the 5th century, the Huns under the Attila conquered south and west of the Carpathian Mountains which left the Slavs north of the Carpathians free to consolidate their new lands.
The Polans tribe gradually dominated the area. In the mid-10th century, the looming spectre of conquest from the Turkic nomads from the east or the Christian Caroliginian Empire in the west convinced the Piast leaders of the Polans tribe that they had to join the family of Christian nations to the west in order to survive. In 966, Miezko I Piast converted to Christianity in order to marry the Czech princess Dobrawa, whose country converted one hundred years before. On 14 April 966, Miezko and Dobrawa were married, and their land was converted, its people baptized, and the country consecrated by the Church (not to mention recorded by the Vatican bureaucracy) as Poland, the “Land of the Polans”.