system of promotion based on seniority. Song argued fervently against it, believing that this would cause capable people to be stuck in low positions, but Emperor Xuanzong did not agree. In 733, Song retired and took residence in Luoyang, and Emperor Xuanzong ordered that full salaries be paid to Song notwithstanding his retirement. In 734, when Emperor Xuanzong visited Luoyang, Song came out of his mansion to greet the emperor, and Emperor Xuanzong had his son Li Huang () the Prince of Rong personally comfort Song, and thereafter frequently sent medicines and delicacies to Song. Song died in 737 and was given posthumous honors. Notes and references Old Book of Tang, vol. 96. New Book of Tang, vol. 124. Zizhi Tongjian, vols. 207, 208, 209, 210, 211, 212, 213, 214. 663 births 737 deaths Chancellors under Emperor Ruizong of Tang Chancellors under Emperor Xuanzong of Tang Mayors of Xi'an