It’s always puzzled me how Richard got this nickname as surely Lions weren’t commonly known about in Western Europe at this time. Were Lions just seen as mythical creatures spoken about in the bible, or was there common knowledge that such an animal existed?
The question of why England has lions on its arms has come up often so maybe these previous answers will help:
There is a section of the FAQ about it
u/jschooltiger also wrote about Why does England have a Lion on their flag, despite the fact there were no Lions in England?, with links to numerous other older answers.