On the passed-away year of Emperor Ly Than Tong and the correct timeline of some historical events in the early 12th century

Abstract

Based on trustworthy historical documents that dated back before Dai Viet su ky toan thu (hereafter Toan Thu), this paper re-corrects the dead year of emperor Ly Than Tong, which was 1137, not 1138 as traditionally believed. The correction of this date leads to all historical accounts in Toan Thu currently dated 1138 must be counted down one year. In addition, this paper reexamines the dates of some historical events that occurred between 1134 and 1140 and suggests their correct timeline.