This document provides a historical biography of Emperor Tang Taizong (Li Shimin) of China from 613-650 CE. It summarizes the emperor's quest for the throne from 613-626, which involved wars against neighboring Koguryo in 613 and struggles against other rivals for power within the Sui dynasty. The first part describes Emperor Yang's launching of a new invasion against Koguryo in 613 from his capital in Luoyang and the initial battle for Liaodong City, a strategic Koguryo outpost, which the Sui forces besieged for 23 days.