Question

What was the most important event during the period of European invasions?

Answer 1

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.

Answer 2

The answer would be the Vikings accepted Christianity. The Viking Age was an age of substantial spiritual change in Scandinavia. It is true that nearly the whole population of Scandinavia was pagan at the start of the Viking Age, but the Vikings had numerous gods, and it was not at all problem for them to accept the Christian god together with their own.