Poland in the Early Middle Ages

The most important phenomenon that took place within the lands of Poland in the Early Middle Ages, as well as other parts of Central Europe was the arrival and permanent settlement of the West Slavic or Lechitic peoples.[1][2] The Slavic migrations to the area of contemporary Poland started in the second half of the 5th century AD, about a half century after these territories were vacated by Germanic tribes fleeing from the Huns.[1][2] The first waves of the incoming Slavs settled the vicinity of the upper Vistula River and elsewhere in the lands of present southeastern Poland and southern Masovia. Coming from the east, from the upper and middle regions of the Dnieper River,[3] the immigrants would have had come primarily from the western branch of the early Slavs known as Sclaveni,[4] and since their arrival are classified as West Slavs and Lechites, who are the closest ancestors of Poles.[a]

From there the new population dispersed north and west over the course of the 6th century. The Slavs lived from cultivation of crops and were generally farmers, but also engaged in hunting and gathering. The migrations took place when the destabilizing invasions of Eastern and Central Europe by waves of people and armies from the east, such as the Huns, Avars and Magyars, were occurring. This westward movement of Slavic people was facilitated in part by the previous emigration of Germanic peoples toward the safer areas of Western and Southern Europe. The immigrating Slavs formed various small tribal organizations beginning in the 8th century, some of which coalesced later into larger, state-like ones.[5][6] Beginning in the 7th century, these tribal units built many fortified structures with earth and wood walls and embankments, called gords. Some of them were developed and inhabited, others had a very large empty area inside the walls.

By the 9th century, the West Slavs had settled the Baltic coast in Pomerania, which subsequently developed into a commercial and military power.[7] Along the coastline, remnants of Scandinavian settlements and emporia were to be found. The most important of them was probably the trade settlement and seaport of Truso,[8] located in Prussia. Prussia itself was relatively unaffected by Slavic migration and remained inhabited by Baltic Old Prussians. During the same time, the tribe of the Vistulans (Wiślanie), based in Kraków and the surrounding region, controlled a large area in the south, which they developed and fortified with many strongholds.

During the 10th century, the Lechitic Western Polans (Polanie, lit. "people of the open fields") turned out to be of decisive historic importance. Initially based in the central Polish lowlands around Giecz, Poznań and Gniezno, the Polans went through a period of accelerated building of fortified settlements and territorial expansion beginning in the first half of the 10th century. Under duke Mieszko I of the Piast dynasty, the expanded Polan territory was converted to Christianity in 966, which is generally regarded the birth of the Polish state. The contemporary names of the realm, "Mieszko's state" or "Gniezno state", were dropped soon afterwards in favour of "Poland", a rendering of the Polans' tribal name. The Piast dynasty would continue to rule Poland until the late 14th century.[6][9]