The toga was a piece of clothing worn on ancient Earth.
In 500 BC, Graham O'Brien, Ryan Sinclair and Yasmin Khan wore togas while meeting Pythagoras in Crotone. Ryan and Yaz found it much easier to wear a toga than Graham did. (PROSE: The Pythagoras Problem)
In Athens in 421 BC, the Seventh Doctor wore a toga. (AUDIO: Mask of Tragedy)
Marc wore a toga whilst living as a slave in 1st century BC. (AUDIO: Tartarus) He switched to "modern" clothes whilst travelling in the TARDIS. (AUDIO: Feast of Fear)