Bases were a form of skirt, worn by upper-class members of the military, that were a striking departure from typical men's costume of the sixteenth century. During this period, most men wore a doublet, a slightly padded short overshirt, with hose and breeches. The bases replaced the hose and breeches. They were made of stiff, heavy cloth, and consisted of panels of fabric, often in alternating colors. The panels were attached to an inner lining in such a way as to make each of the panels either rounded or pleated. These skirts were worn for ceremonial purposes throughout Europe, especially for the large military reviews that allowed European armies to show off their strength. Men typically wore form-fitting leg stockings beneath the bases.
Payne, Blanche, Geitel Winakor, and Jane Farrell-Beck. The History of Costume. 2nd ed. New York: HarperCollins, 1992.