Lore:The Art and the Madness v.1
Though powerful masters of necromancy can reanimate subjects long dead, most practitioners require a fresh subject. This often means most novices require a subject that has passed no more than three days prior. Attempting to raise minions without the proper knowledge of and training in the necromantic arts can result in an incomplete binding of the soul.
The subsequent breaking of the master and minion relationship can be dire for the hapless novice necromancer.