What is the significance of the Treaty of Westphalia in 1648?
The Treaty of Westphalia was the formal ending of the 100 years war between Catholics and Protestants in central Europe. Its resolution is widely known as the beginning of the modern notion of sovereign nation-states being independent of one another. Previous to this the entire continent was united by christianity, but in the Westphalian system each nation had citizens that were loyal to its government first and foremost.
What was the key trigger that prompted Hitler's declaration of himself as führer and absolute dictator of Germany?
The infamous "Reichstag Fire" was the event that catalyzed the nazi ascendance to power. The "Reichstag" was the name for the German Parliamentary building, and on February 27, 1933 it was mysteriously set ablaze at night. The following day Hitler declared that German communists had been the perpetrators and demanded that he be granted special powers and that most civil liberties of German citizens be suppressed. The Nazi party used these new powers to silence political discourse that was contrary to their ideology, and ultimately boosted them into holding the majority of seats in the parliament.
How could one best describe the key differences between the concepts of "ethnic identity" and "national identity?"
Ethnic Identity is a social construct whereby people feel part of a particular group based on shared cultural history or identity. Ethnicity can include some or all of the following: race; religion; language; geographic location; and other things. National Identity is the same thing except that its uniting factor is a common subscription to a political ideology. The two can often help to develop each other - certain political parties are often ethnically homogenous, but ultimately ones political affiliation is seen as more of a choice than ones ethnicity.