The most important reason for the collapse of Rome was the failure to actually integrate what they conquered. When Roman soldiers conquered new lands, it was rare that they ever attempted to force their culture, ideals, or laws upon the natives and barbarians. Thus, when the Empire began suffering internal struggles, the natives they had conquered decided to take action, which lead to the swift collapse by barbarian invasion from all sides. It's hard to pick a LEAST important reason, seeing that there were many of them, but I suppose a contender would most likely be the common refusal of the Empire to even acknowledge that barbarians were rising. On the outer edges of their territory, in places like Gaul and Morocco, the Roman government was reluctant to even recognize the threat of the barbarians, thinking that even accepting that these barbarians were causing trouble would weaken their prestige in the public eye.
The lord would provide to the vassal land from which they could make money from and in return the vassal would contribute troops to the lords army. Sometimes vassals would also pay a small fee of grain or various other goods as a sort of tax for the land.
The Mediterranean climate influence culture in the region by creating a common cuisine throughout the region. The cuisines are mostly seafood which is from the Mediterranean Sea.
Explanation:
The sea and rainfall helped with food and agriculture. Olive oil was popular also!