Foreign attack was one great disadvantage to the Hanseatic Trade as they had their rivalry with Italian businesses and both were trying for supremacy and monopoly on sea route trade in the 13th Century.And because of foreign attacks,the Hanseatic League became very weak and disbanded. And then British and Dutch businesses took control of shipping in the region.
The sentence is not grammatically correct, it should be, "Last summer, Jim mowed one lawn, now he mows three." Mowed just one lawn doesn't make sense in one sentence.