《新唐书·列传·卷四十五》
旧例，每年派兵五百驻守姚州，此地险恶有瘴气，到此即死。
故事，岁以兵五百戍姚州，地险瘴，到屯辄死。
According to the old practice, 500 soldiers were sent to station in Yaozhou every year, but this place is dangerous and full of miasma, and whoever arrives here dies.