A Lord would protect a king and provide wealth in return for land and protection. Knights and nobles would provide protection for serfs and other classes in exchange for labor and production.
This isn't the best thing because this is from google with some of my own words so try swapping words out and replacing some to not get in trouble for plagiarism. Wish you luck though!
The Minoan and Mycenaean civilizations were maritime or sea-going and trading economies. The Mesopotamian civilizations were primarily land locked and dependent upon agricultural economies along with land based trade routes.
