It usually goes something like
HAHA YA KNOW CHRISTIANS KILLED INVADING MUSLIMS ONCE BY OUR STANDARDS THAT'S TERRORISMeven though they were defensive wars (well except in the Baltic but eh)WHO CARES THAT IT WAS ALMOST 1,000 YEARS AGO BAHAHA
And 9/11 is far more relevant given how it's still very important globally
Do you
seriously think that the crusades involved the Muslims invading Europe?
Without muslims having existed: L dead, LIII injured.
Edit: I actually researched this subject:
First crusade: Pope is tired of the Franks fighting, so he sends them off to conquer Jerusalem.
Second crusade: another invasion of the middle east from Europe.
Third crusade: another invasion of the middle east from Europe.
Fourth crusade: the Doge of Venice redirected this one to sack Constantinople. A low point for crusades.
Fifth crusade: another invasion of the middle east from Europe.
Sixth crusade: another invasion of the middle east from Europe.
Seventh crusade: another invasion of the middle east from Europe.
Eighth crusade: this time Europe invades northern Africa.
Ninth and final medieval crusade: yet another invasion of the middle east from Europe.
NONE of the crusades involved a Muslim invasion of Europe. Quite the opposite, in fact.
HOWEVER, there WAS an invasion of Europe via Spain in the 8th century, because Islam was the hot new thing then and they wanted to show everybody that they were cool and could spread like the big religions.