Iolo Fitzowen is most well known for his mastery of the crossbow. However, that doesn't mean that he is content to neglect other ranged weapons. This bow is a special construction made by Iolo from the best available materials and perfectly balanced and weighted. It is a superior weapon, but sadly also the private property of its maker.
In Ultima IX, Iolo gave the Avatar this bow after teaching the final bow technique to the hero. Of course, this was only possible if Iolo had survived the dungeon Despise.