by Jiří Trnka. The clip shows a battle between Czechs and a rival slavic tribe called Luczans. A hero Čestmír goes to battle instead of a cowardly prince Neklan (dressed in his armour, similarly to Patrokles and Achilles). Čestmír defeats the leader of Luczans - Vlastislav, but gets killed afterwards. Inspired by his heroism the Czechs win the battle.
(as far as I know, the only way to get this movie is some DVD company in japan, so I'm sharing this bit - it's a wonderful piece of animation.)