In the 1590s Tatars from the Ottoman Empire pillaged the surrounding countryside. (See Moldavian Magnate Wars, "The Magnate Wars (1593–1617), Causes".) They were unable to overcome the city's fortifications, but their raids started to diminish the city's economic strength and importance. Outbreaks of bubonic plague in the 1620s and the Swedish Deluge in 1655–60 further undermined its prominence. In March 1656, the Poles led by Polish national hero Stefan Czarniecki defeated the invading Swedes under King Charles X Gustav in the Battle of Jarosław. In the Great Northern War of 1700-21 the region was repeatedly pillaged by Russian, Saxon and Swedish armies, causing the city to decline further.