It's just the Outremer Project (also known as the Crusades). The achilles heel of the Outremer Project was that everyone in the Middle East said, 'What the hell are a bunch of Europeans doing around here claiming Israel?'
So, we got a load of Teutonic Knights to knock up some local girls, made up a language (Yiddish) that is pretty similar to Old German, chucked in a bit of Aramaic for good measure and voila. We have an ancient claim on the middle east! Simples.