The silly-Latin "sentence" Semper ubi sub ubi is translated 'always wear underwear,' although ubi means 'where' not '-wear'. If you were dressed as a Roman, would you "semper ubi sub ubi"? Comments on Mary Beard's latest blog address the question of what a Roman would wear under a toga. Someone mentioned the leather bikinis that have been found covering women on mosaics; another, a garment known as a subligaculum, which may be translated as a loincloth; another, a packet of underwear sent to soldiers at Vindolanda. Even if women wore leather bikinis (with or without outer garments), and soldiers wore loincloths under their armor, that doesn't answer the question of whether toga-clad Roman men wore underwear. Read more about this probably unanswerable at What Did Romans Wear Under Their Togas?
What evidence can you cite for or against the idea that Romans wore underwear under their togas?
Hadrian's Wall at Vindolanda image © N.S. Gill