The toga was a distinctive garment (usually woolen) of Ancient Rome. For most of Rome's history, the toga was a garment worn exclusively by men, while women wore the stola. Non-citizens were forbidden to wear a toga.
There were many kinds of toga, each used differently.
Toga virilis, Toga candida, Toga praetexta, Toga pulla, Toga picta, and Toga trabea the wearing of these depended upon your age and social status, and of course, the occasion.
As time went on, the garments in Roman society changed. They adopted the shirt (tunica, or in Greek chiton) which the Greeks and Etruscans wore, made their toga more bulky, and wore it in a looser manner. The result was that it became useless for active pursuits, such as those of war. Thus, its place was taken by the more handy sagum (woolen cloak) on all military occasions. In times of peace, too, the toga was eventually superseded by the laena, lacerna, paenula, and other forms of buttoned or closed cloaks. However, the toga did remain the court dress of the Empire.
Octavian (Augustus), was so incensed at seeing a meeting of citizens without the toga, that, quoting Virgil's proud lines, "Romanos, rerum dominos, gentemque togatam" (Romans, lords of the world, the race that wears the toga), he gave orders to the aediles that in the future no one was to appear in the Forum or Circus without it.