Casimir III the Great was King of Poland from 1333 to 1370, a period of remarkable economic and cultural growth for Europe, which would lay the foundations for the following Golden Age of the Renaissance. Casimir was a skilful monarch and was responsible for a series of enlightened political reforms, which led the Kingdom of Poland to become a beacon of religious tolerance in Europe, with a particular focus on the Jewish community. Many historians trace the reasons for the massive Jewish presence in Poland back to Casimir's reign, which would gradually stabilise over the following centuries, reaching a remarkable 10% of the Polish population in 1939.

Casimir renewed the Statute of Kalisz (of 1264), also enriching it with new interpretations and thus guaranteeing the Jewish community of Poland religious freedom, legal autonomy and protection from unfounded accusations. In a Europe that was still torn apart by anti-Semitic violence and persecution, Casimir's Poland soon became a key refuge for thousands of Jews who gathered under the protection of this enlightened king. Jewish communities in other European kingdoms at the time had not been equally fortunate and in Spain, England and France Jews were often persecuted, massacred and blamed for all evil.

Casimir saw the Jewish community as an important resource rather than a threat, Jews were in the late Middle Ages very active in trade and crafts and contributed to the economic prosperity of Poland. In 1335 in this context, the Kazimierz district of Krakow was created, which became the heart of Jewish culture in Poland. Some unverified rumours and popular stories also speak of a hypothetical relationship of Casimir with a Jewish woman named Esterka, a story more symbolic and metaphorical than really based on established facts. A crucial moment was the arrival of the Black Death in Europe in 1347. The first victims of the plague were the Jews themselves, who were accused of being the cause of the disease and of deliberately poisoning the wells. The ignorance and popular anti-Semitism of many Western Europeans led to massacres and summary killings, but Casimir and Poland forcefully prevented the spread of unfounded accusations by instead welcoming Jewish refugees from other parts of Europe.

Casimir III was the only Polish king to earn the title ‘the Great’. His greatness was not only due to castles, legal codes or territorial conquests, but also to his tolerance and moderation.