At the turn of the 15th century, Jews began to settle in Łuków. Some sources claim that Jews came as early as the mid-13th century. By the 16th century, an organized Jewish community was in place. The first synagogue in the town was built in the 16th century, although it later burned down in a fire. In 1648, the Khmelnytsky uprising as part of the Cossack Uprisings, led by Bohdan Khmelnytsky, resulted in attacks and heavy losses for the Jewish community of Łuków, which also saw numerous marches and stopovers by armies. In 1655, the Jewish community experienced a pogrom, which had been organized by the Muscovites and impacted many parts of Poland. The local community of Łuków had 1000 deaths. The new synagogue was set on fire and many Jewish households were also destroyed. This was followed by the Swedish Deluge (1657), during the war between Poland and Sweden, which involved invasions ordered by King Carl Gustav and his Transylvanian ally, the Rakocy prince. This period brought fatal effects to the town. In April 1657, the town was totally devastated by the invasion of Swedish and Transylvanian troops, and about 1000 Jews lost their lives.