Poland was ruled at various times either by dukes and princes (10th to 14th centuries) or by kings (11th to 18th centuries). During the latter period, kings were elected by the nobility (14th to 18th centuries).

Duke Mieszko I adopted Christianity under the authority of Rome in the year 966. He was succeeded by his son, Bolesław I the Brave, who greatly expanded the boundaries of the Polish state and ruled as the first king in 1025. The following centuries gave rise to the mighty Piast dynasty, consisting of both kings such as Mieszko II Lambert, Przemysł II or Władysław I the Elbow-high and dukes like Bolesław III Wrymouth. The dynasty's rule over Poland ceased with the death of Casimir III the Great in 1370. In the same year, the Capetian House of Anjou became the ruling house with Louis I of Hungary as king of both Poland and Hungary. His daughter, Jadwiga, later married Jogaila, the pagan Grand Duke of Lithuania, who in 1386 was baptised and crowned as Władysław II Jagiełło. After Jadwiga had died in 1399 without surviving children, the Polish hereditary monarchy ended. Władysław remained on the throne as elected king. His descendants continued to be chosen as monarchs by noblemen, creating the Jagiellonian dynasty, and during this time, a personal union between Poland and Lithuania took place.

During the reign of Casimir IV Jagiellon and Sigismund I the Old, culture flourished and cities developed. This era of progress, also known as the Polish Renaissance, continued until the Union of Lublin under Sigismund II Augustus, which unofficially marked the end of the Polish Golden Age. After the death of the last Jagiellonian king, the united Polish–Lithuanian Commonwealth continued the policy of elective monarchy, with mostly foreigners elected as monarchs, such as Henry III of France, who witnessed the introduction of the Golden Liberty system, and Stephen Báthory, a capable military commander who strengthened the nation. The Vasa dynasty, which descended from the Jagiellons, initially expanded the Polish–Lithuanian Commonwealth as the arts and crafts developed, as well as trade and commerce. King Sigismund III Vasa, a talented but somewhat despotic ruler, involved the country in many wars, which subsequently resulted in the successful capture of Moscow and the loss of Livonia to Sweden. His son, Władysław IV Vasa, fiercely defended the Commonwealth's borders and continued the policy of his father until his death, unlike John II Casimir, whose tragic rule resulted in his abdication.

The election of John III Sobieski to the Polish throne proved to be beneficial for the Commonwealth. A brilliant military tactician, John III led the coalition forces to victory at Vienna in 1683 and he partially recaptured land from the Ottoman Empire. However, in the following years, the contested rule of the Wettin dynasty (Augustus II the Strong and Augustus III of Poland) placed the Commonwealth under the influence of Saxony and the Russian Empire. Additional feuds with rebel nobility (szlachta) and most notably Stanislaus I Leszczyński and France diminished the influence of Poland–Lithuania in the region, which led to the partitions that occurred under King Stanisław August Poniatowski, yet another enlightened but ineffective monarch.

During the Napoleonic Wars, Frederick Augustus I of Saxony, ruled as Duke of Warsaw and attempted to rehabilitate the Polish state. After the Congress of Vienna, the territory of Poland was again divided by the Prussia (with the Prussian King as Grand Duke of Posen), Russia (Congress Poland was founded in 1815 with the Emperor of Russia as King of Poland) and Austria (with the Austrian Emperors as Kings of Galicia and Lodomeria). A new Kingdom of Poland was proclaimed as an independent state in 1916 with a Regency Council but the monarchy was abolished and a parliamentary republican authority was established when Poland was re-constituted as a sovereign state in 1918.

Legendary

Most of the legendary Polish rulers appear for the first time in chronicles from the 13th century and their existence has not been determined.

| Unknown | Unknown | Unknown | Legendary founder of the Polish nation according to folktales, tribal leader | Lechites (Tribe)

|Krakusalso Krak or Grakch–

| Unknown | | Legendary founder of Kraków | Lechites (Tribe)

|– | | Son of Krakus | Unknown | | Succession | Lechites (Tribe)

|– | | Son of Krakus I, brother of Krakus II | Unknown | | Succession | Lechites (Tribe)

|also Wąda– | | Daughter of Krakus, sister of Krakus II and Lech II | Unmarried and childless | | Succession | Lechites (Tribe)

| Dukealso Leszek– | | – | Unknown | dated around 700 by Marcin Bielski– | Birth name Przemysław, defeated the Hungarians and was crownedElected | Goplans and Polans (Tribes)

| Duke– | | Presumed son of Leszko I, Alleged progenitor of the Popielids dynasty | Unknown | | Succession | Popielids

| Duke– | | Presumed son of Leszko II | Unknown | | Succession | Popielids

| Duke– | | Presumed son of Leszko III | Unknown | | Succession | Popielids

| Duke–

| NN, A German Princess | | A legendary ruler was dethroned by Piast. He appears (without the number) in the oldest Polish chronicle, from the early 12th centurySuccession | Popielids

| – | | Son of Chościsko | Rzepicha1 child | | Legendary founder of the Piast dynasty. He appears in the oldest Polish chronicle, from the early 12th century | Piast

House of Piast

The three direct predecessors of Mieszko I are known only from the account of Gallus Anonymus, who wrote the oldest Polish chronicle, at the beginning of the 12th century. Though their historicity was once debatable, now historians tend to consider them as actually existing rulers.

| Dukealso Ziemowit–9th century | | 9th centuryPresumed son of Piast the Wheelwrightand Rzepicha | Unknown | 9th century | Named Duke of the Polans after his father, Piast the Wheelwright, refused to take the place of legendary Duke PopielElected | Piast

| Dukealso Leszek or Lestko9th century–10th century | | – 880Presumed son of Siemowit | Unknown | – 950 | Named Duke of the Polans after succeeding his fatherSuccession | Piast

| Dukealso ZiemomysłLatin: Zemomislaus10th century–/960 | | Presumed son of Lestek | Unknown | – 960 | Named Duke of the Polans after succeeding his fatherSuccession | Piast

Mieszko I started his reign as leader of the Polans, while other parts of future Poland were settled by other tribes, such as Masovians, Vistulans, Lendians, Silesians or Pomeranians. During his reign, Mieszko united Polish lands and adopted Christianity, connecting Poland with western Europe. His descendants ruled the state as natural lords and Poland was seen as their hereditary property. Because of that, the state was often divided between the sons of the deceased ruler and eventually united by one of them. Early Polish rulers were not considered equal to Western European kings, so their title is translated as a duke. Some of them managed to prepare a coronation and adopted the title of king, but the effects of those efforts were short lived.

| DukeMieszko ILatin: Misico, dux Wandalorum–25 May 992( years) | | Son of semi-legendary Siemomysł | Doubravka of Bohemia1 child Oda of Haldensleben3 or 4 children | 25 May 992PoznańAged about 62 | First Christian ruler of PolandSuccession | Piast

| KingBolesław I the Bravealso Boleslaus I the Great992 – 1025 (as duke)18 April 1025 – 17 June 1025 (as king)( years) | | PoznańSon of Mieszko I and Doubravka of Bohemia | Unknown, daughter of Rikdag Unnamed Hungarian1 child Emnilda of Lusatia5 children Oda of Meissen1 child | 17 June 1025KrakówAged about 58 | First crowned kingSuccession | Piast

| KingMieszko II Lambert25 December 1025 – 1031( years) | | Son of Bolesław I the Brave and Emnilda of Lusatia | Richeza of Lotharingia4 children | 10/11 May 1034PoznańAged about 44 | Crowned kingSuccessionDeposed by Bezprym | Piast

| DukeBezprym1031 – 1032( years) | | Son of Bolesław I the Brave and Judith of Hungary | Unknown | Aged about 46 | Usurped | Piast

| DukeOtto1032 – 1033( years) | | Son of Bolesław I the Brave and Emnilda of Lusatia | Unknown | Aged about 33 | Country divided, ruler of a Duchy | Piast

| DukeDytrykalso Dietrich and Theoderick1032 – 1033( years) | | Son of Lambert Mieszkowic or Mieszko Mieszkowic | Unknown | Aged about 41 | Country divided, ruler of a Duchy | Piast

| DukeMieszko II Lambert1032 – 1034( years) | | Son of Bolesław I the Brave and Emnilda of Lusatia | Richeza of Lotharingia4 children | 10/11 May 1034PoznańAged about 44 | Country divided until 1033Restored as duke | Piast

| KingBolesław the Forgotten1034 – 1038/1039( years) | | before 1016Presumed son of Mieszko II Lambert | Unknown | 1038/1039 | Semi-legendary, existence disputed | Piast

| DukeCasimir I the Restorer1034/1040 – 1058( years) | | 25 July 1016Son of Mieszko II Lambert and Richeza of Lotharingia | Maria Dobroniega5 children | 19 March 1058PoznańAged 41 | Made prince in 1034, returned from abroad in 1040Restoration | Piast

| KingBolesław II the Generous1058 – 1076 (as duke)26 December 1076 – 1079 (as king)( years) | | 1042Son of Casimir I the Restorer and Maria Dobroniega of Kiev | Unknown1 child | 2/3 April 1081Hungary or OssiachAged about 39 | Crowned king in 1076Deposed and exiled in 1079 after slaying Stanislaus of Szczepanów | Piast

| DukeWładysław I Herman1079 – 4 June 1102( years) | | 1044Son of Casimir I the Restorer and Maria Dobroniega of Kiev | Unknown1 child Judith of Bohemia1 child Judith of Swabia3 children | 24 June 1102PłockAged about 58 | Succeeded brother after his exile | Piast

| DukeZbigniew (duke of Poland)1102 – 1107( years) | | Son of Władysław I Herman and Przecława (?) | Unknown | 8 July 1113Aged about 40 | Country divided, ruler of a DuchySuccession | Piast

| DukeBolesław III Wrymouthalso Boleslaus III1102 – 1138( years) | | 20 August 1086PłockSon of Władysław I Herman and Judith of Bohemia | Zbyslava of Kiev1 child Salomea of Berg12 children | 28 October 1138SochaczewAged 52 | Country divided until 1107SuccessionHis death led to the fragmentation of Poland | Piast

Fragmentation of Poland (1138–1320)

After a period of fights between brothers and unstable inheritance, Bolesław III Wrymouth decided to formalize succession. According to his testament, the state was divided into provinces – one for every son and a Senioral Province with the capital city Kraków. The testament established two principles on which the new order in Poland was based: principate and seniorate. One duke, the princeps (also called in English high duke), had supreme authority over other dukes and ruled the senioral province. This princeps should be the oldest member of the dynasty, not necessarily the son of the predecessor. During the time of fragmentation, both principles were abolished. Seniorate was formally abolished in 1180 during the assembly of dukes and bishops in Łęczyca, when Casimir II the Just was made hereditary high duke. The Principate was de facto ended in 1227 with the assassination of Leszek I the White, after which local dukes no longer respected suzerainty of the high duke.

| High DukeWładysław II the Exile1138 – 1146( years) | | 1105KrakówSon of Bolesław III Wrymouth and Zbyslava of Kiev | Agnes of Babenberg5 children | 30 May 1159AltenburgAged 54 | Duke of SilesiaSuccessionDeposed and exiled | Piast

| High DukeBolesław IV the Curly1146 – 1173( years) | | Son of Bolesław III Wrymouth and Salomea of Berg | Viacheslava of Novgorod3 children | 5 January 1173Aged about 51 | Duke of Masovia 1138Succeeded, exiled half-brother | Piast

| High DukeMieszko III of Poland1173 – 1177( years) | | Son of Bolesław III Wrymouth and Salomea of Berg | Elizabeth of Hungary, Duchess of Greater Poland Eudoxia of Kiev | 13 March 1202KaliszAged about 75 | Duke of Greater Poland 1138SuccessionDeposed by his brother in 1177 | Piast