The peace agreement with Castile largely held for almost twenty years. In 1248, Muhammad demonstrated his commitment to Ferdinand by sending a contingent to help the Castilian conquest of the Muslim-held Seville. In 1252, Ferdinand died and was succeeded by Alfonso X. In 1254, Muhammad attended a "Cortes", or an assembly of Alfonso's vassals, at the royal palace in Toledo, where he renewed his promise of loyalty and tributes as well as paying homage to Alfonso's newborn daughter Berengaria. During his reign, Alfonso was more interested in other enterprises—including a series of unsuccessful campaigns in Muslim North Africa—rather than renewing the conflict with Granada. Muhammad met with Alfonso at the latter's court in Seville every year, and paid his annual tributes. Muhammad used the ensuing peace to consolidate his new emirate. Though small in size, the Emirate of Granada was relatively wealthy and densely populated. Its economy was focused on agriculture, especially silk and dried fruit; it traded with Italy and northern Europe. Islamic literature, art and architecture continued to flourish. The mountains and desert that separate the kingdom from Castile provided natural defenses, but its western ports and the northwestern route to Granada were less defensible.