"You spot a lone man, a poacher by the looks of him, running from two men on horseback. Of course, they catch the poacher and drag him to the ground, binding his arms. They throw the criminal on a horse and ride away, but they forgot something. You approach, considering yourself lucky that they left the hunter's Longbow behind."
The Longbow is an artifact from Heroes of Might and Magic IV, giving heroes +5 ranged attack.
The Longbow is a slightly improved Crossbow. Again, its main use is to provide ranged attack to heroes who aren't skilled with Archery. Unlike the Crossbow, however, the Longbow doesn't eliminate penalties. This makes it less attractive for those without Archery, but it is better than the Crossbow on long term, because the damage bonus provided is bigger and the penalties are removed by advanced expertise in Archery.