Most historical sources indicate that Zhang Jun, like his father Zhang Shi and his uncle Zhang Mao, continued to use Emperor Min of Jin's era name "Jianxing" (both to show continued allegiance to Jin and to distance himself from Emperor Yuan of Jin and his line) but some sources indicate that he changed era name to "Taiyuan" (太元 tài yuán 324–346). A current theory is that his era name was used internally while the "Jianxing" era name was used when communicating with other states.