The fortifications of the monastery-stronghold known as Fortalitium Marianum allowed it to withstand a 40 days long siege in 1655 40 day by the Swedish army during the large-scale invasion of Poland popularly known as the Swedish Flood. The spectacular defence of Jasna Góra encouraged the whole nation to take up arms and led to victory over the Swedes. From that time on the cult of the painting of Our Lady of Jasna Góra grew, and the Jasna Gora stronghold became not only a military stronghold and centre of religious cult, but a centre of patriotism and national traditions as well.