The Probert Encyclopaedia of Warfare

ARQUEBUS

The arquebus was a hand-gun similar to, but longer than, a musket and of larger calibre. It fired a two ounce ball, and was fired from a forked rest which fitted to a hook of iron fastened to the barrel. A larger variant which took a heavier ball was used in fortresses. When Henry VIII established the yeoman of the guard in 1485 he armed half of them with arquebuses, the other half with bows and arrows.
Research Arquebus