In the XI century, Leon and Catalonia were considered the strongest Christian states on the Iberian Peninsula

In the XI century, Leon and Catalonia were considered the strongest Christian states on the Iberian Peninsula, and in the XIII century they lost the primacy to Castile, Portugal and Aragon. Why did it happen?

León was the first to start the Reconquista, and Catalonia, with its seaside towns, was the richest and most cultural region of Catholic Spain. But later, the front of the advancing Catholics moved to the south and the southern border principalities began to strengthen due to the seizure of Muslim lands.