First take it to one of the larger auction houses and get an expert valuation. I cannot say which as I do not know your country of origin. By just putting it on an online auction site it may sell for a trifle of it`s real value. Unfortunately even if it is old and precious to you it may have little commercial value so don`t build your hopes up till you get expert valuation. But I hope it is by a collectable maker and you get a fortune.