Treaty of Versailles: The War Guilt Clause. Article 231 of the Treaty of Versailles, known as the War Guilt Clause, was a statement that Germany was responsible for beginning World War I.
The Treaty of Versailles included a "war guilt" clause that completely blamed Germany for World War I and made them suffer the aftermath of it.
The Treaty of Versailles completely put the blame on Germany for causing World War I, although Germany thought otherwise. Germany believed that they were just as responsible as all of the other countries involved.
This treaty is known for being very harsh on Germany. They had to owe very large sums of money, give up a lot of their army and weapons, and numerous nations they took during World War I.
Germany ended up being very hurt by this treaty and their economy started to plummet. This made a lot of Germans angry against the Allied nations and Germany ended up breaking the treaty, which eventually lead to World War II.
Very abbreviated answer: The Black Death was another name for the plague, this claws caused by rats and lead to death of a large sum of the population.