The kings of europe during the middle ages seemed obsessed by creating alliances thru marriages. I can think of a few examples where this spectacularly failed, and examples where it apperantly did work. But has anyone actually tried to do a statistical analysis to see if countries actually did have fewer conflicts when allied thru a marriage?
In the middle ages the only form of alliance was marriage. This basically allowed the dynasties to be intertwined and also allowed for inheritances so it was quite effective. The main issue with its relative effectiveness is that nations were smaller so there should be more wars,.