When to capitalize "European":
* As part of a proper noun:
* Examples: European Union, European Parliament, European Commission.
* When referring to a specific region or group of people:
* Examples: "She studied European history," "The European nations have a rich cultural heritage."
When to NOT capitalize "European":
* As an adjective describing a general concept:
* Examples: "European art," "European languages."
* As a noun referring to the continent in general:
* Example: "Europe is the second-smallest continent."
In doubt? If you're unsure, it's generally safe to err on the side of capitalization.