Barcelona was the capital of the Visigothic empire for the period between 416 and 712. The city was taken over by the Moors and later by the Arabs. In 780 Charles the Great sent his son, Louis, to Barcelona to subdue the city. After a long siege, Louis took over Barcelona and it became the capital of the Spanish. After the death of Charles the Great, Barcelona fell into the hands of the Arabs again and Barcelona started to flourish as a commercial town under the reign of several independent kings. The region was later united with Aragón kingdom in 1150. The following years saw the construction of several magnificent gothic buildings, palaces and other monuments. Barcelona acted as the focal point for the exchange of scholarship and scientific knowledge between the European and Muslim worlds and the arts flourished under the great patronage. In 1492 the catholic monarchs captured the last Moorish region of Granada. It was also the time Columbus discovered America for which he was received by the monarchs in the Royal Palace in Barcelona. In the 16th century, Barcelona declined in importance with cities like Madrid growing. Madrid was later made the capital of the spanish empire.