Mieszko I (c. 935 – May 25, 992) was the first Grand Duke of Poland of the Piast dynasty (c. 960 – 992) and the founding father of Poland.
Mieszko I was the son of the semi legendary Polish prince Semomysl. His real name is not Mieszko, but Meichiswav. He largely unified the territory of Poland. He once fought against the Lutycy or Wilcy Slavic tribes in order to gain control of Pomerania; He once competed with the nobles of Bohemia for Silesia and Lesser Poland. To resist the Holy Roman Empire founded by Otto the Great, Mieszko I formed an alliance with Bohemian Duke Boleslav II. Mieszko I was the most outstanding emperor in Polish history, revered as the "Father of Poland" by later generations.

Mieszko I, also known as Mieszkov I (922-992). The first Grand Duke of Poland of the Piast dynasty (reigned approximately 960-992). Son of Siemomysl. In 964, Mieszko I married Dobrava, the daughter of Bohemian Duke Boleslav I. Probably influenced by his Christian wife, Mieszko I was baptized in 966 and established Christianity (Catholicism) as the state religion of Poland.
Mieszko I hoped to rely on his alliance with Bohemia to resist the possible threat of Holy Roman Emperor Otto I, but in 963 he was forced to submit to Otto I. In 973, Mieszko I swore allegiance to the Emperor again after being defeated by Otto I's son, Emperor Otto II.
In 981, Mieszko I lost a portion of his territory in the war with Grand Prince Vladimir Sviatoslavich of Kiev. After the death of Otto II in 986, Mieszko allied with the new emperor Otto III.
In 992, Mieszko I placed Poland under the protection of the Pope in a document before his death.

During the reign of Mieszko I, the largely unified Greater Poland (now the central and western regions of Poland) consolidated and expanded the Polish national territory in the long-term struggle against the invasion of German feudal lords. Silesia, Mazovia, Pomorie, and the Vistula River basin were all incorporated into Poland's territory, becoming one of the major Slavic countries. In 966 AD, Mieszko I accepted Christianity and introduced Latin, which promoted the feudalization of the country and the development of culture.

Polish people belong to the western branch of the Gusla people and have lived in the western plains of Eastern Europe since ancient times. Compared to its neighbors in Western and Southern Europe, Poland is a relatively late formed country.
After the mid-9th century, two major "tribal duchies" gradually formed in this region, the Vistula Duchy in Lesser Poland and the Polish Duchy in Greater Poland. The Duchy of Poland was ruled by the Piast family. In 963, Mieszko I of this family became a prince, and under his leadership, a new page was opened in Polish history. Mieszko devoted his life to unifying Poland politically and religiously, but he also faced very powerful opponents, including Holy Roman Emperor Otto I.
After ascending to the throne, Mieszko first unified Greater Poland and Kuyati, but he faced a strong challenge in unifying Pomorie in the Oder River estuary area and was once defeated.
In 972, he finally defeated the state of Viyalte in Western Pomerania and unified Pomerania by defeating the German lord H ö odo in the Battle of Caidini. [2]
In 990, he defeated the Czech prince Boleslav II and occupied Silesia. Later, his son, the brave Boleslav I, unified the small Polish region centered around Krakow, finally completing the cause of unifying Poland.

In addition to political unity, religious unity is also important. Polish people originally believed in primitive religions such as the god of fire, but with the formation of the country and the development of civilization, Poland also began to stand at the doorstep of Christianity. At that time, Holy Roman Emperor Otto I had been striving to make Christianity in Poland subordinate to the Archdiocese of Magdeburg in Germany, which was consistent with his consistent policy of eastward expansion in politics.
In order to maintain Poland's independence, while deciding to accept Christianity, Mieszko decided to accept Christianity from the Czech Republic according to Latin rituals for geopolitical reasons.
In 965, Mieszko married Dubrava, the daughter of Czech Grand Duke Boleslav I. The following year, Mieszko and all court officials received baptism from Czech clergy. Under his leadership, Poland accepted Christianity nationwide and became a member of the Christian civilization, greatly enhancing Poland's status and cultural development in Europe.
With the efforts of Mieszko, in 968, a diocese was established in Poznan, Poland, directly under the jurisdiction of the Roman Catholic Church, rather than under the Archdiocese of Germany.

Before Mieszko, although the unified language and economic culture of Poland had been formed, it faced the threat of the German eastward movement and the pressure of surrounding Slavic countries, and it was still unknown in what form unification would be achieved. Thanks to Mieszko's efforts, the outline of Poland as a country became clear on the map. Afterwards, Poland was once divided and, after reunification, became an important power in Central and Eastern Europe, serving as a crucial link in regional checks and balances for a long time. The formation of the Polish nation-state occurred against the backdrop of the gradual formation of neighboring ethnic states. The historical achievements of Mieszko I lie in expelling foreign forces, delineating the general boundaries of the Polish nation-state, and having a significant impact on Polish culture in terms of national spirit and religion.