In 1335, the Polish king Casimir the Great founded the new town of Kazimierz. Interestingly, it was located literally next to the then capital of Poland, Kraków. Today, the former thriving town is one of its districts. For centuries, Kazimierz was mostly inhabited by Jews.

In the unanimous opinion of historians, King Casimir the Great of Poland, in addition to the many internal reforms implemented to strengthen the position of the state, is also regarded as a protector of the Jews.  Many of them settled in Kazimierz, a town founded by the monarch next to Kraków, the then capital of Poland. 

Granted by the monarch in Sandomierz, the foundation charter of 27 February 1335 is assumed to be the beginning of its existence. The area of Kazimierz was a marshy island located between the Vistula and its old river branch. This created natural defence possibilities, strengthened by the construction of the city walls. Such a location also influenced the security of Krakow itself and the royal castle on the Wawel Hill from the southern side. Kazimierz was not much inferior to the Polish capital in terms of area – 50 hectares to 65 hectares. Within its boundaries there were three pre-existing settlements along with churches, including one dedicated to St. Michael on Skałka – the alleged site of the martyrdom of St. Stanislaus. 

From the end of the 15th century, Kazimierz was settled by the Jewish population, who migrated here from, among others, nearby Bohemia and Moravia, but also from Italy or other countries. By the end of the 16th century, their number had reached 2,000 inhabitants. In 1495, the Old Synagogue was built on Szeroka Street. 

After King Sigismund III Vasa moved the capital of Poland from Krakow to Warsaw, the importance of Kazimierz also declined. During the partition period at the turn of the 18th and 19th centuries, the Austrian authorities led to the abolition of the separation and the incorporation of Kazimierz into Kraków.