《明史·志·卷四十四》
嘉靖十年，册立九嫔，册符用银，大小小于皇妃的五分之一，用黄金装饰。
嘉靖十年，立九嫔，册用银，杀皇妃五分之一，以金饰之。
In the tenth year of the Jiajing era, nine imperial concubines were granted seals of silver which were five times smaller than those of an imperial concubine, and were decorated with gold.