The first Jews are believed to have arrived in Poland in the 9th century, following the Black Death pandemic which decimated the country's population. By the end of the 13th century, there were already significant Jewish communities in many Polish towns and cities. Over the next few centuries, the Jewish population of Poland continued to grow, reaching a peak of around 3.5 million in 1939. This made Poland home to the largest Jewish community in Europe at the time.