What is the importanced of the edict of milan issued by the emeror constantine in 313 ad?

1: how did the rise of rulers with total power in europe and asia lead to world war 2?

In what way did expansion and global trade during the 15th to 18th centuries affect the economies of european countries?

Why did un coalition troops battle iraqi forces in 1991? iraq had invaded saudi arabia, along with its other border nations.iraq had invaded kuwait, which was a major source of the world's oil.the united nations wanted to remove saddam hussein from power.the united nations wanted to prevent the trade of illegal drugs.