with about 1600 kg of mosaic tesserae as a gift. The mosaicist trained some of the caliph's own craftsmen, who eventually became skilled enough to do the work on their own. The work was finished by this team in late 970 or early 971. Al-Hakam II's work on the mosque also included the commissioning of a new minbar (pulpit) in 965, which took about 5 to 7 years to finish. Unfortunately, the details of its construction and of its chronology are muddled by sometimes contradictory historical sources. Ibn 'Idhari, for example, implies that Al-Hakam had two minbars built in this period, with one of them possibly having been destroyed or replaced. Either way, whichever minbar survived and became associated with the mosque was celebrated by many writers for its craftsmanship. It was made out of precious woods like ebony, boxwood, and "scented" woods, and it was inlaid with ivory and with other coloured woods such as red and yellow sandalwood. Modern scholars believe the minbar had wheels which allowed it to be rolled in and out of its storage chamber. The mosque's last significant expansion under Muslim rule was ordered by Al-Mansur (Almanzor), the autocratic vizier of Caliph Hisham II, in 987–988. Rather than extending the mosque further south, which would have been impossible due to the proximity of the riverbank, Al-Mansur had the mosque extended laterally towards the east, extending both the courtyard and the prayer hall by 47.76 meters and adding eight naves to the mosque. Once again, the same design of double-tiered arches was replicated in the new construction. The capitals produced for the hundreds of new columns, however, have a simpler and less detailed design that may reflect the hurry in which they were produced. The new extension covered 8600 square meters and made the mosque the largest in the Muslim world outside of Abbasid Iraq. The new eastern wall of the mosque featured ten richly-decorated exterior portals similar to the ones on the mosque's western side, although these were heavily restored in the 20th century. Al-Mansur also famously looted the bells of the Cathedral of Santiago de Compostela and reportedly ordered them to be melted down and turned into chandeliers for the mosque, although none of these chandeliers have survived. Later Islamic history of the mosque (11th–12th centuries) After the collapse of the Umayyad Caliphate in Cordoba at the beginning of the 11th century, no