What is the significance of the emergence of palaces? How did kings gain power over priests? How did they keep it?

To consolidate power to themselves

Explanation:

The emergence of palaces was a move by the kings to fortify their monarchies. The kings were often worried about how to perpetuate their power. In addition, they were concerned about how their children and families would live after they were gone. Thus, after the defeat of the pope by Napleon's general, the church had no more power to control monarchies. They concentrated the power to themselves.

Palaces were demonstrations of wealth, the kings gained power over priests by sheer power, and they kept it through sheer power.