This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Approximately one-third of East Prussia's population died in the plague and famine of 1709–1711, including the last speakers of Old Prussian. The plague, probably brought by foreign troops during the Great Northern War, killed 250,000 East Prussians, especially in the province's eastern regions. Crown Prince Frederick William I led the rebuilding of East Prussia, founding numerous towns. Thousands of Protestants expelled from the Archbishopric of Salzburg were allowed to settle in depleted East Prussia. The province was overrun by Imperial Russian troops during the Seven Years' War.
What wiped out one third of East Prussia's population during the early 1700's?