I have been reading a history of Scotland and there is much made of the various English-Scottish battles that left thousands of men dead (937 Battle of Brunanburh, 1297 Battle of Stirling Bridge, 1314 Battle of Bannockburn, etc.). I am left wondering what happened to all those that were killed. In modern warfare, there seems to be an effort to retrieve (and bury) the dead. What happened in the era before 'modern' warfare?