While the Doctor is obviously one of the most important aspects of any given era of Doctor Who, the importance of the companion should never be overlooked. From classic companions like Jo, Sarah Jane and Ace, to the modern companions like Martha, Donna and Bill, the companion is just as important to the continued success of the show as the Doctor is.
During it's nearly 60-year run, Doctor Who has dived into examining the relationship between companion and Doctor in some very interesting ways, such as with Clara Oswald. Initially introduced during Matt Smith's era, Clara started out as more of a mystery to be solved than a character in her own right. However, things got more interesting during Peter Capaldi's era.
The show examined what would happen if the companion tried to act like the Doctor, with dangerous results. During her time on the show, Clara became increasingly more reckless and carefree, and the Doctor would even end up breaking many of his rules to save her.
Clara's arc definitely caused a lot of discussion among Whovians, but how well do you remember her time in the TARDIS? Take this quiz to find out!