Construct Rune

For five minutes, the caster chants a poem to use the spell. This spell allows the caster to magically inscribe a rune of sealment on an object. This rune lasts for 24 hours; it makes an object almost unbreakable. The longer the spell has been cast within the 24 hours, the weaker it will become. However, only the strongest of men would be able to break a rope with this spell cast on it that is almost at the 24 hour limit.