عبد الرحمن الأوسط
In the 9th century a series of Norman attacks (Vikings) occurred on the peninsular coasts, one of them in Seville. This motivated Caliph Abd ar-Rahman II to reinforce the wall of Isbylia (Seville) (of Roman origin) and to create a permanent war fleet. To this end, he ordered the construction of some shipyards in Seville: