Someone in the Arab world read their history carefully, and is undoubtedly laughing his rear end off at the symmetry of the situation.

One piece of driving force of the Crusades was "What the heck do we do with all these uppity younger sons?"

Now, I know that this is only one piece, usually ignored under the religious, political, and economic issues, but it was a piece of the European motivation. Looks like the Islamic violent fundamentalist extremist terrorist criminal elements (or whatever Dept. of State wants us to call them this week) jumped on this population control technique.