Although never formally crowned king, Mieszko I was the first prince of Poland for whom there are historical records. He came from the royal House of Piast, which had reigned in Gniezno, capital of Poland at the time, since the early 10th century. Assuming power around the age of 30, the young prince established a well-managed and strong state following the example of his principality's southern and western neighbours, Bohemia, Moravia and Germany, setting up a developed territorial administration and a strong military force.

At the time, Mieszko's state, with a territory of approx. 200,000 sq. km, comprised the lands of the Polanians on the lower River Warta, the Goplanians around Lake Gop³o, the Mazovians on the Rivers Bzura and Vistula, the Ledzianians in the environs of the strongholds of Sandomierz and Przemy¶l, and the Pomeranians. However, a country along a coastline located almost in the centre of Europe was an enviable prize for its neighbours. Being a wise politician, Mieszko decided to enter an alliance with one of the regional powers of the time, the Kingdom of Bohemia. A treaty, sealed by the marriage of Mieszko and Dobrawa, daughter of the Czech prince, was to protect Poland not only from incursions from the south, but also to provide an ally in the event of war with the German Emperor Otto I.

In 966 Mieszko was converted to Christianity and received baptism from the Czechs. A document preserved in Italy addressed to the pope and with an account recorded at a somewhat later time in the Middle Ages relating to the conversion of Poland, was inscribed "Dagome Iudex", where the enigmatic epithet Dagome (maybe a corrupted version of his name miscopied by an Italian scribe, and/or a palaeographic acronym in Latin meaning "I, Mieszko, by the grace of God, judge ..." )refers to Mieszko. Mieszko's entire realm became Christian. A new metropolitan archdiocese was set up at Gniezno, whereby the Polish Church became directly answerable to the Pope, and not subordinate to the German archbishop of Magdeburg, who had hoped themselves to convert the lands on the eastern marches of the Holy Roman Empire to Christianity.

Nonetheless, the lords of Germany did not give up attempts to subjugate the Polish territories. However, luck was on the side of the Poles. On 24 June 972 Mieszko defeated Margrave Hodo at Cedynia. In 979 he reached a peace accord with Otto II which, after the death of Dobrawa, was sealed by his marriage to Oda, a daughter of a German margrave. In 986 he provided support for the regency of Otto III during his minority. At the same time, he sought allies further afield, marrying his daughter to King Eric of Sweden.

Mieszko's internal policy was equally prudent. He created a strong state authority and a strong army (according to the Jewish traveller Ibrahim Ibn Jaqub, his permanent guard consisted of three thousand warriors). He became famous for erecting an entire system of fortifications and defensive strongholds, and founded churches in Gniezno and Poznañ.
Having done so much for his country, he died on 25 May 992, leaving a well-organised and strong state.

Facts Perhaps "Mieszko" was not the real name, but a nickname of the Polish prince. It is either a shortened old Polish name "Mies³aw" or a nickname derived from the noun for blacksmith's bellows, a small bag (sack), or a honey-eating bear. Using a nickname instead of the proper name was believed to protect the prince from failure and bad luck.