Sunderland manager David Moyes has resigned following the club's relegation from the Premier League.
The end of the Black Cats' 10-year stay in the top flight was confirmed when they lost to Bournemouth last month.
Moyes, 54, informed chairman Ellis Short of his decision to step down at a meeting in London on Monday.
"I wish the players and my successor well in their efforts towards promotion back to the Premier League," said Moyes.
Former Everton and Manchester United boss Moyes took charge in July last year, after Sam Allardyce left to become England manager.
Sunderland finished bottom of the table this season with 24 points, having won only six games.
"I pursued the services of David Moyes for a considerable period prior to his appointment last summer, which makes the announcement of his departure difficult for everyone concerned," said owner Short.
He said that Moyes was not taking compensation for his departure, calling it a "testament to his character".
"In the days ahead we will take some time for reflection, and then focus on recruitment and pre-season as we prepare for our Championship campaign. We wish David well in the future," added Short.
However, earlier this month he suggested he would stay with the club in the Championship next season, saying: "I know what needs to be done to get back in the Premier League."
In a club statement on Monday, Moyes said: "I would like to thank Ellis Short and the Board for giving me the opportunity to manage Sunderland and the fans for always being so passionately supportive of their club."
This is the first time Moyes has been relegated as a manager, having warned supporters just two games into the season that his squad would struggle.
BBC Sport chief football writer Phil McNulty
David Moyes' departure from Sunderland after a desperate season ended in relegation carried an air of inevitability - and it is only a minor blessing for the Black Cats that the decision has been taken so quickly after its conclusion.
It is a sign of how his stock has fallen that since he was awarded a six-year contract to succeed Sir Alex Ferguson at Manchester United in 2013 he has been sacked at Old Trafford, again at Spanish side Real Sociedad and now has a relegation and resignation on his CV at Sunderland.
And there are still two years left on that original Manchester United contract.
Moyes looked a solid appointment in succession to Sam Allardyce but set the negative tone he adopted for the entire campaign when he flagged up a relegation fight after only two games.
Sunderland's football was drab and draped in defeat. The only shining lights were leading scorer Jermain Defoe and promising young goalkeeper Jordan Pickford - who now look certain to follow Moyes out of the door.
Moyes made some defiant noises about taking charge of Sunderland in the Championship but in the end his unpopularity with fans who had suffered all season, plus the embarrassment of relegation, left him with nowhere to go but away from Wearside.