Some will tell you the Black Watch was a Scottish regiment whose name is a reference to the color of its tartan. An equally plausible explanation, however, is that the regiment was established to keep an undercover watch on rebellious Jacobites. The Gaelic word for black is dubh, meaning, in this case, "hidden" or "covert." A wide range of uniforms, weaponry, and marching banners are displayed. The castle is closed on the last weekend in June.