《后汉书·本纪·光武帝纪上》
六月初七，封贵人郭氏为皇后，子刘强为皇太子，大赦天下。
六月戊戌，立贵人郭氏为皇后，子彊为皇太子，大赦天下。
On June 7th, he enfeoffed his concubine Guo as the empress, and his son Liu Qiang as the crown prince and granted amnesty to the whole country.