《北史·本记·卷七》
武明太后刚怀宣帝时，每夜有红光照亮内室，太后私下十分奇怪。
武明太后初孕帝，每夜有赤光照室，太后私怪之。
When Empress Wuming was pregnant with Emperor Xuan, a red light illuminated the inner chamber every night, and the empress was privately amazed by this.