The legendary New York Times fashion critic Cathy Horyn announced on Friday that she is resigning with immediate effect. As industry news goes, this is huge. Horyn has been fiercely outspoken since she took up the role in 1999, and could always be relied on for an honest opinion – so honest that it often caused industry scandal.

In a world in which publications rely heavily on advertisers, it's rare to find a journalist giving out scathing critiques as often as they hand out praise. The bluntness of Horyn's views made them an unmissable read. Her exit means a significant change to the landscape – there's no doubt she'll be remembered, alongside the likes of Diana Vreeland and Carmel Snow, as one of the voices that shaped fashion journalism. Here are the must-know facts about the woman once described as 'fashion's most feared critic'.

Horyn started out as a news journalist. She was in her mid-twenties, pregnant, and single when she got her first fashion reporting job for the Detroit News. 

She is a long time champion of Raf Simons, which indirectly led her into a high-profile feud with Hedi Slimane. In a 2004 review she argued that Simons' work had paved the way for Slimane's. Eight years later when Slimane launched his debut collection for Saint Laurent, Horyn was not invited to the show.

This unfolded into a public dispute. Horyn wrote about the apparent snub and Slimane posted a personal response on Twitter, noting among other takedowns that 'I also hear that her sense of style is seriously challenged'.

And it's not just the Saint Laurent show at which she's found herself unwelcome. At various times, Horyn has been banned by Carolina Herrera, Giorgio Armani, Dolce & Gabbana, Helmut Lang, Nicole Miller and Oscar de la Renta.

De la Renta told WWD that he felt Horyn's work, which often includes some discussion of the celebrities on the front row, contained 'personal commentaries and digs, not only about the designers, but about people who attend the shows'. One review particularly upset him. Horyn referred to him as 'a hot dog' (she later clarified that she meant it 'as in someone showing off his tricks, like an athlete'); de la Renta responded by taking out a full page ad in WWD in which he described her as 'a stale 3-day old hamburger'.

When Versace dressed Lady Gaga for her Edge of Glory video, Horyn advised Donatella Versace to 'be choosier' in who she lends clothes to. This provoked a series of retaliations from Gaga.

Gaga singled Horyn out in a 2011 article for V magazine. She wrote: 'In the age of the Internet, when collections and performances are so accessible to the public and anyone can post a review on Facebook or Twitter, shouldn’t columnists and reviewers, such as Cathy Horyn, employ a more modern and forward approach to criticism, one that separates them from the average individual at home on their laptop? ... Why have we decided that one person’s opinion matters more than anyone else's?'

She followed up with a slightly less classy touch: adding the lyric 'Cathy Horyn, your style ain't d***' to her song Cake Like Lady Gaga.

Horyn is in a relationship with Art Ortenberg, the widower of designer Liz Claiborne. He weighed in on the Gaga feud.

In a letter to WWD, he wrote: 'True, Cathy Horyn is my girlfriend. Nevertheless, I feel it necessary to cudgel Gaga for her badly informed, dumbing-down opinion that an uninformed opinion is as valid as that of a seasoned critic ... [as though] any professional critic is just another opinion and that Gaga’s vacuous thoughts deserve the same status. Grow up, Gaga.'

Horyn is leaving her job in order to spend more time at home with Ortenberg, who has recently had health problems. Judging by that valiant effort to defend her, he sounds like a keeper.

There was a media backlash when she applied her critical skills to an unlikely subject: Snooki, a reality star from Jersey Shore. In a long profile, Horyn wrote that 'trying to hold a conversation with Snooki is a little like getting down on your hands and knees with a child. You have to come down to her level, and sometimes you almost think you need to bribe her with a piece of candy to coax her to be more responsive. She is really only responsive to her own immediate needs and desires.'

In a scathing response in Salon, the journalist Mary Elizabeth Williams advised Snooki, 'You may be feeling a bit down and out after being called a “yowling” “berserk windup toy.” Trust me, it’s not you — it’s that bitch from the paper of record.'

Horyn acknowledges that she's a harsh critic, and puts it down to her own high standards. Speaking of her former colleague Amy Spindler (who was style editor of The New York Times Magazine), she told The Daily Beast that 'We have standards. We want people to be not just good but very good. And I can be tough on people, sometimes too tough, especially with the most creative.'

She's working on a fashion history book. According to a statement from The New York Times, it's 'A book to be published by Rizzoli that chronicles how The New York Times has covered fashion from the 1850s to the first decades of the 21st century.'

If it's anything like her work to date, it's likely to be a must-read.