She's part of a literary dynasty that has dominated English literature for nearly 200 years, her sisters' books are on the national curriculum and hardly a Christmas goes by without a Brontë adaption. So why has Anne Brontë been forgotten? I know, I know, you haven't forgotten her, you read her all the time, you've got Agnes Grey in your hand right now. But in comparison to her sisters, Anne is not read. Her books aren't on the curriculum, she only shows up in must-read lists in combination with her famous siblings and most people would struggle to name her other book (The Tenant of Wildfell Hall).

The problem with Anne was that she refused to glamorise violent, oppressive men. While Charlotte and Emily were embracing the concept of the brooding, abusive byronic hero, Anne preferred quiet, supportive men. Her heroes are curates and farmers, men who look after their mothers and resist the temptation to imprison or exile unwanted wives.

The contrast between Anne and her sisters is perfectly summarised by comics artist Kate Beaton of Hark! A Vagrant fame. In Dude Watchin' With the Brontës Charlotte Brontë and Emily Brontë are checking out some hunks as their younger sister, Anne, watches with growing frustration. "What about that one?" purrs the author of Jane Eyre, as a Mr Rochester figure skulks past. "The guy was an asshole," observes Anne. "What about that one?" simpers the author of Wuthering Heights, as a Heathcliff lookalike lurches into view. "If you like alcoholic dickbags," Anne retorts. "You are so inappropriate … no wonder nobody buys your books," snap her sisters.

The comic will elicit sniggers of recognition from anyone who's suffered through the vitriolic alcoholics in Charlotte and Emily Brontë's novels. The hero in The Tenant of Wildfell Hall sits in sharp contrast to Heathcliff from Wuthering Heights: Gilbert Markham helps Helen flee from her abusive husband, while Heathcliff abuses his pregnant wife to the point that she runs away. Markham reluctantly accepts Helen's decision not to marry him; Heathcliff takes out a 20-year-long revenge policy when Cathy does them same.

Charlotte and Emily were undoubtedly feminist in their views and the way they felt about their writing; Charlotte frequently had to be restrained by her publishers from writing to critics who reviewed her gender rather than her books. But for the most part they kept their feminism off the page, focusing upon brutal male characters whose main appeal tended to be their potential for redemption. Anne, however, was far more explicit about her feminism, and she wrote about men who expressed their love in words, rather than by dominating the women in their lives.

Charlotte and Emily's fascination with violent men, and Anne's aversion to them, can be traced back to their brother, Branwell Brontë. Whenever anyone scratches their head over how three daughters of a country parson managed to write with such passion and insight about human nature, my eyes start rolling. With a brother like Branwell – handsome, charming, alcoholic – the sisters were provided with more than enough inspiration. The different ways in which they interpreted Branwell's behaviour is where it gets interesting.

The seductive nature of a happy ending can't be disputed, and the two older Brontës provide it in spades. In Wuthering Heights, Heathcliff and Cathy are never united, but their children fall in love: Heathcliff's behaviour is almost justified, as it has brought Linton and Cathy mark II together. Likewise in Jane Eyre, Mr Rochester falls in love with Plain Jane, attempts to commit bigamy, is thwarted, his wife luckily burns to death and they live happily ever after. Charlotte and Emily offered their fictional Branwells a form of redemption that in reality he failed to achieve.

Anne, the sister who spent the most time nursing Branwell, either refused or was unable to romanticise what happened to her brother. In The Tenant of Wildfell Hall an abused wife, Helen Graham, runs away from her alcoholic husband, Arthur Huntingdon. She meets Gilbert Markham and falls in love with him but is unable to marry him. Anne's depiction of Arthur Huntingdon's decline drew heavily on Branwell's death and still stands out today as an unflinching depiction of alcoholism.

By romanticising their alcoholic, violent brother, Charlotte and Emily Brontë were presenting an optimistic view of the byronic hero. Anne Brontë, however, refused to wear rose-tinted glasses. As a novelist she is more honest than Emily and more unflinching than Charlotte, but that doesn't make for great romance or cosy TV adaptations. It's easy to say that because Anne refused to give us a brooding hero, her books are less widely read. But I would suggest that she was in fact just too honest about the nature of violence and addiction.