With the Reconquista in full swing after the conquest of Córdoba in 1236, the Nasrids aligned themselves with Fernando III of Castile, officially becoming the Emirate of Granada in 1238. Most historians agree that Granada became a tributary state to the Kingdom of Castile from that year, although this was often interrupted by wars between the two states. Integrated within the European mercantile network, the ports of the kingdom fostered intense trading relations with the Genoese, but also with the Catalans, and to a lesser extent, with the Venetians, the Florentines, and the Portuguese. It provided connections with Muslim and Arab trade centers, particularly for gold from sub-Saharan Africa and the Maghreb, and exported silk and dried fruits produced in the area. The Nasrids also supplied troops from the Emirate and mercenaries from North Africa for service to Castile.