Like many people associated with Doctor Who for its nearly 49 years of existence, actors who’ve played companions to the wandering Doctor may choose depart from show, but they never fully leave it.

Yes, fandom is sometimes difficult. Science fiction fans are loyal, adoring and sometimes over the top, but in the end, they love the character as much as they love the actor who plays them, which is why, at this time, our hearts hurt to learn of their passing. And the fact that is, in the last eighteen months, Doctor Who has lost four beloved actors who played enduring roles on the cult show in the 1970s –Nicholas Courtney, Elizabeth Sladen, Caroline John and now Mary Tamm.

Tamm, who joined the show for season sixteen as Romanadvoratrelundar (Romana for short), passed away on July 26, after an 18 month battle with cancer. She was 62. Like Elizabeth Sladen, like Caroline John,  her illness was kept secret from the press and fandom.

When she joined the show in 1978, it was at a crossroads. After fifteen successful seasons, the series was showing its age. While Tom Baker was well settled into the role after four years, the producers were trying to figure out how make the show fresh for his fifth year. So for season sixteen, they came up with The Key to Time arc (something proposed by producer Graham Williams two years earlier). For the first time in the shows history, the entire season would be linked under an umbrella theme.

And at first, Tamm was not keen on the idea of playing a companion to the Doctor. While the 1970’s companions began to change, grow and become more three dimensional than their 1960’s counterparts, at times they still were the typical damsel in distress. But producers assured her that Romana, a fellow Time Lord, would be just as smart and capable as the Doctor. And at first, you could see they were sticking to that. But a little more than halfway through the twenty-six episode season, the writers seemed to forget who Romana was and her character began to de-evolve into the more traditional assistant role, with nothing in site to prove they had any intention of developing the character further. So as the season wound down, she decided not to return for season seventeen, though her departure was not announced until after filming had already been completed.

But fortune favored the production team, as Lalla Ward –who played an instrumental role in the six episode season ending serial, Armageddon Factor- was asked to take over the role for the next season. According to an interview with Tamm back in 2007, she was willing to film a regeneration scene to help smooth the transition between her and (eventually) Lalla Ward, but said she was not invited to do so, and that she believed that producer John Nathan-Turner created a false rumor that she was pregnant and thus that was why she was not coming back.

After leaving the series, Tamm took leading roles in two BBC dramas, The Treachery Game and its sequel The Assassination Run.  A leading role in the sitcom The Hello, Goodbye Man opposite Ian Lavender was produced in 1984. She was also on the soap Brookside between 1993 and 1996, as well as many guest-star roles on various TV series.

Tamm continued her association with the show through the audio plays of Big Finish, reprising Romana for the Companion Chronicle: The Stealers from Saiph in 2009. This was followed by Ferril’s Folly and Tales from the Vault in 2011. She also returned as Romana in Big Finish’s second series of The Fourth Doctor Adventures featuring Tom Baker, which will now be released posthumously this January.

She is survived by her husband, Marcus Ringrose, daughter Lauren and grandson Max.