Guo Shoujing
After Kublai Khan was proclaimed Khagan at his residence in Xanadu on May 5, 1260, he began to organize the country. Zhang Wenqian, a central government official, was sent by Kublai in 1260 to Daming where unrest had been reported in the local population. A friend of Zhang's, Guo Shoujing, accompanied him on this mission. Guo was interested in engineering, was an expert astronomer and skilled instrument maker, and he understood that good astronomical observations depended on expertly made instruments. Guo began to construct astronomical instruments, including water clocks for accurate timing and armillary spheres that represented the celestial globe. Turkestani architect Ikhtiyar al-Din, also known as "Igder", designed the buildings of the city of the Khagan, Khanbaliq (Chinese "Dadu"). Kublai also employed foreign artists to build his new capital; one of them, a Newar named Araniko, built the White Stupa that was the largest structure in Khanbaliq/Dadu.