More specifically, this was worn at the times at and around the rule of the Antonines, since the togas of the period were far too voluminous and bulky to use in military service. It was held together by a safety-pin, or fibula (I don't know if this has any connection to the bone of the same name; I'm guessing not) on the right shoulder. Commanders wore a larger, purple-dyed version of the sagum called a paludamentum.