Some historians that study the history of the Three Kingdoms periods argue that while Guan Yu, Zhang Fei, Huang Zhong, Ma Chao and Zhao Yun were appointed to the similar military rankings and were listed in the same volume in the historical texts, their military achievements are significantly differed, and people referring those five generals as "Five Tiger Generals" presume that they share the same accomplishments. Kaiyu Luo of Sichuan University argues that while Guan Yu had led armies of over 200,000 soldiers to expand Shu Han's territory, Zhao Yun had never stepped out of Shu Han's capital city in his military career: it does not make sense to presume Guan Yu and Zhao Yun had the same level of achievements or to group them together under one "Five Tiger Generals" ranking.