More advantages of the crossbow It could be loaded and be ready to fire long before it was needed whereas it took time for a regular bowman to load his weapon. It was more accurate than a bow because the crossbowman could use two hands to aim it. He didnt have to apply pressure like a bowman had to do when drawing the bow string back.

Disadvantages of the Crossbow It took time to draw the bowstring back so it's fire rate was slower than a regular bow. This improved over time but still was a disadvantage. The Crossbow was also more complex and it needed skill to build so they were less readily available to common soldiers.

A variation on the Crossbow was the Arbalest which was a siege engine version (Much Larger and more powerful) Read more about the Arbalest

Ever thought about making your own crossbow? I have some wonderful pictures of a hand-made crossbow that is carved in the shape of a dragon. Doesn't get much better than this! Check out the pictures here: The Medieval Dragon Crossbow

Interested in making your own crossbow, catapult, slingshot or other type of projectile weapons? Take a look at this book:

The Practical Guide to Man-Powered Bullets: Catapults, Crossbows, Blowguns, Bullet-Bows and Airguns (Available at Amazon.com)