Spain is not a particularly great example; I'd categorize it very much as an evolution of the preceding feudal traditions. The country was born out of a marriage alliance between Castile and Aragon, and familial ties continued to govern a significant chunk of Spain's foreign policy throughout the early modern era, whether that is marriages into Portugal, into the Habsburg Holy Roman Empire, or the French Bourbons, or the whole confusing mess of Italian adventures with Naples et al. Spanish national identity still carries a lot of these fractures from the medieval regions that were never melded completely together - Basque and Catalonian autonomy movements are the prime example.