Casimir III the Great: The King Who Rebuilt Poland, 1333–1370

Casimir III, known as Casimir the Great (in Polish, Kazimierz Wielki), ruled the Kingdom of Poland from 1333 to 1370. Inheriting a small, war-torn and threatened kingdom, he used diplomacy to make peace with powerful neighbours, expanded to the south-east, built castles and towns, codified the law and in 1364 founded the university in Kraków. He was the last king of the Piast dynasty and the only Polish monarch to be called “the Great”.

Background: a kingdom reunited

For nearly two centuries after 1138, Poland had been divided among rival Piast dukes. Casimir’s father, Władysław I the Elbow-high (Łokietek), reunited much of the country and was crowned king in Kraków in 1320. But the restored kingdom was fragile. It had lost Gdańsk Pomerania to the Teutonic Order in 1308–1309, Silesia was falling under Bohemian control, and King John of Bohemia claimed the Polish crown for himself.

Casimir was born on 30 April 1310 at Kowal in Kuyavia. When his father died in 1333, he inherited a kingdom at war with both the Teutonic Order and Bohemia. He was crowned in Wawel Cathedral, Kraków, on 25 April 1333.

Peace through diplomacy

Casimir judged that Poland could not win wars on every frontier at once. His first priority was to end them on acceptable terms.

At meetings in Trenčín and Visegrád in 1335, hosted by his brother-in-law and ally Charles Robert, King of Hungary, John of Bohemia gave up his claim to the Polish throne in return for a payment and Casimir’s acceptance of Bohemian rule over most of Silesia. This painful renunciation was confirmed by later treaties.

With the Teutonic Order, Casimir first sought papal arbitration. The papal court ruled in Poland’s favour in 1339, but the Order ignored the judgement. In the Treaty of Kalisz of 1343, Casimir accepted that the Order would keep Gdańsk Pomerania and the Chełmno land, while Poland regained Kuyavia and the Dobrzyń land. The peace held for the rest of his reign.

Expansion to the south-east

Having secured his western and northern borders, Casimir turned south-east. After the last ruler of Galicia-Volhynia died in 1340, Casimir led campaigns into Red Ruthenia, the region around Lviv. Rivalry with Lithuania over the area lasted for decades, but by 1366 Poland held Red Ruthenia and parts of Volhynia. These lands, with their Orthodox population, made the kingdom larger and more diverse, and Lviv grew into an important trading city.

Reforms at home

Law. Casimir had the customary laws of the kingdom written down in the Statutes of Wiślica for Lesser Poland and of Piotrków for Greater Poland, issued around the 1340s–1360s. They were the first major written codes of Polish law and helped unify justice across regions.

Towns and castles. Casimir encouraged trade, granted town charters and founded new towns, including Kazimierz beside Kraków in 1335. The chronicler Jan Długosz credited him with building around 50 castles and fortifying many towns. Długosz also wrote, in a phrase still quoted in Poland, that Casimir found a Poland of wood and left it of brick or stone.

Economy. He reformed the coinage, issuing the Kraków grosz, and regulated the royal salt mines of Wieliczka and Bochnia, which provided a large share of the crown’s income.

Learning. On 12 May 1364 Casimir founded the Kraków Academy, Poland’s first university, with papal approval from Urban V. It struggled after his death but was refounded in 1400 and is today the Jagiellonian University.

Minorities. In 1334 and later, Casimir confirmed and extended the privileges granted to Jews in 1264 by Bolesław the Pious, guaranteeing protection and self-government. Poland became one of the main destinations for Jews fleeing persecution in Western Europe, especially after the violence that accompanied the Black Death. He was also remembered as “king of the peasants” for attempting to limit abuses by nobles.

The Congress of Kraków

In 1364 Casimir hosted a famous gathering of rulers in Kraków, including Emperor Charles IV, Louis I of Hungary and the kings of Denmark and Cyprus. The meeting dealt with disputes in Central Europe and plans for a crusade, and it showed how far Poland’s standing had risen. According to tradition, the merchant Mikołaj Wierzynek hosted a lavish banquet for the guests.

Family and succession

Casimir married four times: Aldona (Anna) of Lithuania, Adelaide of Hesse, Christina Rokiczana in a marriage of doubtful legality, and Jadwiga of Żagań. He had daughters but no legitimate son. Under agreements made in 1339 and later, the crown was to pass to his sister’s son, Louis I of Hungary.

Casimir died in Kraków on 5 November 1370, after a hunting accident, and was buried in Wawel Cathedral. Louis I became King of Poland, and his daughter Jadwiga later took the Polish throne and married the Lithuanian grand duke Jogaila, founding the Polish-Lithuanian union.

Key people

Casimir III the Great (1310–1370), King of Poland from 1333, the last ruler of the Piast dynasty that had governed Poland since the 10th century.

Władysław I the Elbow-high (1260/61–1333), his father, who reunited the Polish duchies and restored the monarchy in 1320.

Charles Robert of Hungary (r. 1308–1342), Casimir’s brother-in-law and ally, who hosted the Visegrád meeting of 1335.

John of Bohemia (r. 1310–1346), the blind king who claimed the Polish crown until 1335 and later died at the Battle of Crécy.

Louis I of Hungary (r. 1342–1382), Casimir’s nephew and successor in Poland from 1370.

Legacy

Casimir’s reign is often seen as the moment when Poland became a significant Central European power. By most estimates the kingdom he left was more than twice the size of the one he inherited, mainly because of the gains in Red Ruthenia, and it was united by common laws and a shared royal administration. The idea of the “Crown of the Kingdom of Poland” as a state separate from the person of the king took firm shape during his reign.

His castles, many now ruined, still dot the Polish landscape, especially along the so-called Trail of the Eagles’ Nests in the Kraków-Częstochowa Upland. The district of Kazimierz in Kraków, later the centre of Jewish life in the city, preserves his name. Polish historians and writers from Długosz onwards have presented him as the model of a wise, peace-seeking ruler, and the Jagiellonian University honours him as its founder.

Myths and facts

The Black Death. It is often said that Casimir’s quarantine measures spared Poland from the plague of 1347–1351. There is no reliable evidence for such measures, and historians now think Poland was affected, though the scale is debated.

Esterka. A popular legend tells of Casimir’s love for a Jewish woman named Esterka. It is not supported by contemporary sources and first appears in later chronicles.

Timeline

• 1310, 30 April: Casimir is born at Kowal.
• 1333, 25 April: Coronation in Wawel Cathedral.
• 1335: Agreements of Trenčín and Visegrád with Bohemia and Hungary; Kazimierz is founded.
• 1340: First campaign into Red Ruthenia.
• 1343: Treaty of Kalisz with the Teutonic Order.
• 1364, 12 May: Foundation of the Kraków Academy.
• 1364: Congress of Kraków.
• 1370, 5 November: Casimir dies in Kraków; Louis I of Hungary succeeds.

Why it matters

Casimir the Great transformed a fragile, recently reunited kingdom into a stable and respected Central European state. His legal codes, fortifications, towns, university and tolerance of minorities laid foundations for Poland’s later union with Lithuania and its golden age under the Jagiellonians, building on a Christian kingdom that began with the Baptism of Poland.