The answer is: effective secondary source document"
Within 20 years, historians would have enough time to gather all facts and data from all sides that involved in historical event. All of these facts and data is useful for them to decipher how the historical events were unfolded.
This make the chart an effective source to find for information regarding the event. But, since it does not made by people who actually involved in the events, it could only be considered as a secondary source.
In politics this is being "radical" is considered being extreme
Christianity was the dominante religion in sweden
After the attack on Pearl Harbor on the morning of December 7th, 1941, there aren't exact numbers on how many voluntarily enlisted, but it was reported that the lines extended for blocks outside of the recruiting offices.
Before the Protestant Reformation, the Roman Catholic Church was the ultimate authority regarding all thought and it was considered infallible. When Martin Luther questioned the authority of the church it cast doubts on its infallibility. This paved the way for alternative thinking.
