The Thirty Years' War had caused starvation throughout Germany, and by 1630 Greifswald's population had shrunk by two-thirds. Many buildings were left vacant and fell into decay. Soon, other wars followed: the Swedish-Polish War and the Swedish-Brandenburg War both involved the nominally Swedish town of Greifswald. In 1659 and 1678, Brandenburgian troops bombarded the town. The first bombardment hit mainly the northeast part of town, wrecking 16 houses. The second bombardment leveled 30 houses and damaged hundreds more all over the city. Cannonballs of this second bombardment can still be seen in the walls of St Mary's Church.