Question: What is the name of the elder brother emperor that signed the Truce of Ratisbon?
Sentence (from "Yelü Lihu"): Yelü Lihu (耶律李胡) (911-960), also named Honggu (洪古), courtesy name Xiyin (奚隱), formally Emperor Zhangsu (章肅皇帝), was an imperial prince of the Khitan Liao state.
Relevant evidence: No