《旧五代史·后唐·皇纪下》
天祐二年春，契丹阿保机开始兴盛，武皇召见他，阿保机领部族三十万到云州，和武皇在云州东边相会，握手甚欢，结为兄弟，十天后回去，留下一千匹马，牛羊数万，约好初冬大举行动南渡黄河。
天祐二年春，契丹安巴坚始盛，武皇召之，安巴坚领部族三凡十万至云州，与武皇会于云州之东，握手甚欢，结为兄弟，旬日而去，留马千匹，牛羊万计，期以冬初大举渡河。
In the spring of the second year of Tianyou, the leader of the Khitan people Abaoji began to rise. Emperor Wu summoned him, and Abaoji led 300,000 of his tribesmen to Yunzhou. He met Emperor Wu in the east of Yunzhou, shook hands joyfully, and became sworn brothers. Ten days later he returned, leaving behind 1,000 horses and tens of thousands of cattle and sheep. They agreed to make a large move in early winter to cross the Yellow River to the south.