《明史·本纪·卷二》
六月一日，太祖素服草屦，步行祷告山川坛，露宿三天，在西庑还斋。
六月戊午朔，素服草屦，步祷山川坛，露宿凡三日，还斋于西庑。
On the first day of the sixth month, the founding emperor wore plain clothes and straw sandals and walked to the Mountain and River Altar to pray. He stayed for three nights and returned to the fasting temple in Xiwu.