Chris Hughton has been sacked by Brighton after four-and-a-half years as the club's manager.
The 60-year-old led the Seagulls to Premier League survival this season, but they stayed up by just two points after winning only 11 points in 18 games in 2019.
Hughton's assistant Paul Trollope and first-team coach Paul Nevin have also left the club.
Brighton chairman Tony Bloom said: "Chris has done an excellent job, first stabilising our club - reaching the play-offs in his first full season - securing our first ever promotion to the Premier League, and retaining our status in two successive seasons.
"Undoubtedly this has been one of the most difficult decisions I have had to make as chairman of Brighton, but ultimately one I have made due to how we struggled in the second half of the season.
"Our run of three wins from 23 Premier League matches put our status at significant risk. It is with that in mind, and the performances during that period, that I now feel it's the right time for a change.
"Chris will always be very fondly remembered by Albion staff and fans as one of our club's finest and most respected managers.
"I would like to wish Chris, Paul and Paul - who have all worked extremely hard throughout their time here - every success for the future, and thank them on behalf of everyone at the club.
"They will always be welcome at the Amex, and will be remembered here with great affection."
Hughton was appointed in December 2014 and kept the club in the Sky Bet Championship in his first campaign, before achieving promotion to the top flight in 2017.
The former Ireland defender led Brighton to 15th position in their first season in the Premier League, amassing 40 points in the process.
However, despite signing nine new players, including club-record purchase Alireza Jahanbakhsh, the Seagulls finished two places and four points worse off this campaign.
Brighton's poor form in 2019, where they took 11 points from a possible 54 compared to 25 points in the first half of the season, sealed Hughton's fate.
The club have confirmed the search for Hughton's successor is underway.
The former Tottenham player's sacking means there is now just one BAME manager in the Premier League - Wolves' Nuno Espirito Santo - while there are just three in the EFL.