Answer;
Vikings accepting Christianity
Most important event during the period of European invasions is the vikings accepting Christianity.
Explanation;
At the beginning of the Viking Age, almost the entire population of Scandinavia was pagan, however the vikings had many Gods and it was not a big deal for them to accept the Christian god alongside their own.
The conversion of Vikings to Christianity occurred without violence, by the end of the Viking age most vikings had become fully Christian and were baptized and buried in that faith.
The 1 one which is ballad of a teenage queen
Do we drop the atomic bombs on the Japanese, or lead a offensive on the beachs of japan. (He later chose to drop the atom bombs, to save american lives.)
Renaissance was the time period of art and learning. Hope it help!