Query: Who was the ruler when the new city wall was constructed?
Context: Balansiyya had a rebirth of sorts with the beginning of the Taifa of Valencia kingdom in the 11th century. The town grew, and during the reign of Abd al-Aziz a new city wall was built, remains of which are preserved throughout the Old City (Ciutat Vella) today. The Castilian nobleman Rodrigo Diaz de Vivar, known as El Cid, who was intent on possessing his own principality on the Mediterranean, entered the province in command of a combined Christian and Moorish army and besieged the city beginning in 1092.