What major world event caused europe to enter a new era called the middle ages?

The Franks settled in modern France and western Germany. What major world event caused Europe to enter a new era called the middle ages? What effects did the physical geography of Europe have during the middle ages?

a agree i agree becuase it is very importnat for example it can tlel you about your past for exmaple   the first culture was the semerians which people are sitll tryignt o uncover there secrets the wall is just anohter treasure that has thousnads of secrets in it to be uncovered

answer: in 1900, there were no "workplace safety laws"!

explanation: at the beginning of this century, workers in the united states faced remarkably high health and safety risks on the job.

a century ago in 1900 about three hundred out of every one hundred thousand miners were killed on the job each year.

[industria] developments occurred within a legal and regulatory climate that diminished employer’s interest in safety. as a result, americans developed production methods that were both highly productive and often very dangerous.