The Crown of Aragon, which arose from the marriage of Ramon Berenguer IV of Barcelona to Peronella, daughter of Ramir I of Aragon, marked the birth of a military power capable of carrying out military expansion into Muslim territory. The conquest of New Catalonia brought about a significant wave of migration southwards. New religious orders, such as the Cistercians and the Carthusians, or military religious orders, such as the Templars or Hospitallers, helped to organise the conquered territories.

The expansionist policy of Barcelona was also directed towards Occitania. The political ties beyond the Pyrenees soon became cultural links. Catalonia entered fully into the culture of the troubadours. However, these political bonds were broken by the French crusade against the Cathar heretics and the Catalan-Occitanian defeat at Muret.