Though a decorated and generally successful commander, the biggest moment in Iroh's military career was his failed Siege of Ba Sing Se. After laying siege to the great city for six hundred days, Iroh managed to breach the Outer Wall, the first to ever achieve such a feat. However, before Iroh could breach the Inner Wall, his son, Lu Ten, was killed on the front lines. Iroh lost his fighting spirit and abandoned the siege, which ultimately came to be seen as a failure and terrible dishonor for the once decorated general.