A lot of soldiers, north and south, in the civil war would pin a piece if paper with their name on their coat before battle. But it was thought to be an ominous sign that they did not expect to live or win the battle

Throughout medieval times this was one of the goals of heraldry, that is being able to identify nobles from their coat of arms emblazoned on their clothing. As for the common soldier there was not much to distinguish the dead, mainly because nobody cared about them