In attempting to understanding the ideas and institutions of the period of history that is usually called the “Middle Ages” it must be kept in mind that this covers a time frame that easily is divided up into smaller periods, each of which can be seen to have its own unique characteristics and qualities.
Studying the ancient Romans, we find their main contribution has been seen to be the legal order upon which is founded part of the Western economic traditions of property and exchange.
I recently toured Portugal and Spain, where the clashes between civilizations and “little ice ages” were especially violent. The effects of climate change on the Iberian Peninsula over the centuries vividly demonstrate why we should not fear global warming: The effects of any plausible warming scenario for the coming decades will only be positive and contribute to human flourishing. They always do.