《贞观政要·卷三·论择官》
房玄龄等人于是拟定出文武官员共六百四十人，唐太宗接受了这个数额，并对房玄龄说： 从今以后，如果谁有音乐、杂艺等一技之长，超过一般人的，只可以赏赐给他们钱财丝帛，一定不可奖赏过度，授予他们官职。从而让他们和朝廷的栋梁之才并肩而站，同桌而食，致使绅士、大夫引以为耻。 
玄龄等由是所置文武总六百四十员。太宗从之，因谓玄龄曰： 自此倘有乐工杂类，假使术逾侪辈者，只可特赐钱帛以赏其能，必不可超授官爵，与夫朝贤君子比肩而立，同坐而食，遣诸衣冠以为耻累。 
Therefore Fang Xuanling and others drafted a list of 640 civil and military officials. Emperor Taizong of the Tang Dynasty accepted this number and said to Fang Xuanling: "From now on, if anyone has a special skill in music, juggling and so on, and surpasses ordinary people, they can only be rewarded with money and silk, and their rewards must not be excessive or they will be given official positions. This will cause them to stand shoulder to shoulder with the pillars of the court and eat at the same table, making gentlemen and high officials feel ashamed."