Massacre of Canadian Army Medical Corps personnel after the sinking of HMHS Llandovery Castle and the evolution of modern war crime jurisprudence.

SUMMARY: Events after the sinking of the hospital ship Llandovery Castle on June 27, 1918, by the German submarine U-86 outraged Canadians. Survivors aboard a single life raft gave evidence that many of the 234 souls lost had made it to lifeboats but were rammed and shot by the submarine. Many of those who died were nurses. Three German officers were charged with war crimes after the war. The submarine's captain evaded capture. The remaining two officers' defence that they were following the captain's orders failed and they were convicted. This ruling was used as a precedent to dismiss similar claims at the war crime trials after the Second World War. It is also the basis of the order given to members of modern militaries, including the Canadian Armed Forces, that it is illegal to carry out an illegal order.