A more thorough explanation:

Definition: Fetial law is a branch of Roman law that deals with matters related to the relationships between different peoples or nations. It covers topics such as treaties, embassies, and declarations of war.

Examples: One example of fetial law in action is when a nation sends an embassy to another nation to negotiate a treaty. The fetial law would govern the conduct of the embassy and the terms of the treaty. Another example is when a nation declares war on another nation. The fetial law would dictate the proper procedures for making such a declaration and the consequences of doing so.

Explanation: Fetial law is concerned with the legal aspects of international relations. It provides guidelines for how nations should interact with each other in matters such as treaties and war declarations. The examples illustrate how fetial law would apply in these situations, ensuring that the actions of nations are conducted in a legal and orderly manner.