When people ask about my favorite Doctor Who companion, I’m always tempted to say Steven Taylor — even if he’s not always right at the top of my list.

He’s a little overlooked these days, as most of his episodes are missing, but I find Steven one of the most important characters in Doctor Who. People make a big deal about the importance of Patrick Troughton’s performance, and they’re right to. Troughton not only made the show his own; he sold the idea that the show could continue without its title character.

The thing is, although the Doctor was the title character, until very late in Hartnell’s run he was never really the lead. The original protagonist of the show wasn’t the Doctor, but the team of Ian and Barbara. When they left, so left the audience’s main identification point — and at that time an unreliable, trickster wizard wasn’t a viable alternative. The Doctor was the foil, not the lead. He provided tension for the main character to butt against.

Following the tremendous success and goodwill that William Russel and Jacqueline Hill had brought to the show, Peter Purves had a huge burden to take on in becoming the show’s new de facto lead — and he succeded with aplomb, taking on both Ian’s action role and Barbara’s social conscience, continuing her work in confronting the Doctor, demanding that he become the unambiguous hero that he would have to by the time that Steven left.

Although his writing was famously inconsistent, as main companions go Steven is one of the most rounded in the show’s history. He is very outspoken and self-directed, but he is also reasonable and savvy, and quick to defer to the Doctor’s experience — at least, where he believes that the Doctor knows what he is talking about. His anger with the Doctor’s misbehavior is also a thing of legend, and after Barbara’s extensive lesson plan in humility, it served as the final blow to the Doctor’s outsized imperious streak. After The Massacre, the Doctor is a changed man — just a few serials before he would be literally, and this new perspective could bloom from within a new vessel.

I’ve always got time for Steven. Even if he’s not usually my favorite, he’s right up there. And I think his significance in the show’s history is far undervalued.