How might a second-born son hope to achieve success under the system of primogeniture?

In the system of primogeniture, the oldest son inherits from the parents (that is, usually  the father).  That means that other sons have to look for "luck" in other places. This usually meant being trained to be a knight (and hope to start a new family line) or, more rarely, becoming a priest and hoping for a career in the church. 

What do you need with? ? try to review those chapters and quiz yourself using flashcards to retain the information

They were constantly being overlooked as a people and were being controlled by people who weren't really native to their homeland.