What is the main conflict in Poland by James A. Michener?

Much of this book examines conflict in Poland's history. Poland had no national borders and no strong central government. Their king was hired from other countries because the magnates feared that a strong king with an inherited lineage would threaten their own autonomy. The magnates viewed the situation in terms of what was good for them was good for all of Poland. There was never an army that was able to defend the country until King Jan Sibelski. This is why Poland was always easy prey for invaders.