A historian would use a calendar when he is trying to find the dates of when the event occurred, such as the dates of a battle, natural disaster, or how long a type of government has ruled.
hope this helps
False
Back in time (cave people) used many tools, and more people, (tribes, etc.)
The Great Plague transformed Europe because it caused people to be very cautious not to catch the deadly disease and later on, it killed thousands of people which made some people feel lucky to be alive. This also has made an impact on history because this is such an important time that we hear about and we find it very interesting that a sickness could have killed thousands.
Hope this helps!!!:)