[skissane]

I'm honestly not sure how much the events of the Crusades really contribute to the contemporary Israeli-Palestinian conflict.

The Crusades were a rather belated attempt by Christians to reconquer the territories they had lost to Islam – over 400 years after that initial Islamic conquest. They succeeded in the short-term – the Christian Kingdom of Jerusalem endured for almost 90 years, and they managed to hang on to the coastal city of Acre (now in Israel's Northern District) for almost another hundred – but were ultimately unsuccessful.

Whereas, the current Israel-Palestine conflict is primarily a Jewish-Muslim conflict, not a Christian-Muslim one. There is a small Christian minority on the Palestinian side, but Palestinian Christians have no particular links to the Crusades; nor do Israeli Jews or Zionism have any particular link to it. Some of the Crusades (especially the First) involved antisemitic pogroms-but there were plenty of other pogroms in European history which had nothing to do with the Crusades, and by the time Zionism came along, other more recent instances of antisemitism were much more of a motivating factor than any of those as historically distant as the Crusades by then were. So, the Crusades were really a rather different historical chapter without much to do with the current one.

[lenkite]

Depends on your definition of crusade and success. https://en.wikipedia.org/wiki/Reconquista - without that Spain would still be Islamic, so would Portugal.

[skissane]

Historians disagree on how to define “the Crusades”. The traditional definition only includes Christian attempts to reconquer “the Holy Land”, and by that definition the Reconquista was a separate thing. Other historians support broader definitions which include the Reconquista, wars against the remnant non-Christian populations of the Baltics, religious wars against Christian heresies such as the Cathars/Albigenses and proto-Protestants such as the Hussites, etc

However, given that the historical crusades in Israel/Palestine have rather dubious relevance to the contemporary conflict, other “crusades” fought thousands of kilometres away are of even more dubious relevance