Answer by taking a quote from the following article:

Joseph Kevin Keegan, OBE (born 14 February 1951) is an English former football player and manager. A forward, he played for several clubs including Liverpool and Hamburger SV. He went on to manage Newcastle United, Fulham and Manchester City, winning promotion as champions in his first full season at all three clubs. He also managed the England national team.

Keegan's transfer to Hamburg was agreed between the FA Cup final and the European Cup final of 1977, although Keegan had negotiated a maximum transfer fee the season before. On his arrival in Germany, Keegan was the highest paid player in the country, and was built up by the press and club as the "saviour" of Hamburg. He scored in pre-season friendlies against Barcelona and former club Liverpool, but the club suffered defeat in the European Super Cup against the Merseysiders, and Keegan was sent off in a mid-season friendly against VfB Lubeck after knocking out an opposition player with a punch. An unhappy first few months at the club gave way to a more successful season. Although the club finished tenth in the league in 1977-78, Keegan's 12 goals helped him pick up a personal honour, the France Football European Footballer of the Year award for 1978.  The 1978-79 season saw a vast improvement on the club's 1978 finish. New manager Branko Zebec imposed a tough training regime, and Keegan's increasing grasp of the German language, coupled with the newly imposed discipline meant that Hamburg finished as league champions for the first time in nineteen years. The club's success also translated into individual recognition for Keegan, who picked up the European Footballer of the Year award for a second consecutive year, as well as the nickname Mighty Mouse from the fans, after the cartoon superhero.  Hamburg's European campaign of 1979-80 saw Keegan score two goals to help Hamburg past Dinamo Tbilisi, Soviet champions who had beaten Liverpool to reach the latter stages. The club lost to Nottingham Forest in the final in Madrid, however, and this was coupled domestically with being beaten to the Bundesliga title by Bayern Munich. Having negotiated a maximum transfer fee of PS500,000 in his contract the year before and agreeing a move in February, Keegan left Hamburg for Southampton in the summer of 1980.  On 10 February 1980, Lawrie McMenemy called a press conference at the Potters Heron hotel, Ampfield to announce that the European Footballer of the Year would be joining Southampton in the forthcoming summer. The news caused surprise throughout the world of football and around the city of Southampton, as Southampton were a relatively small club. The club were beginning to become established in the top division, but this signing showed how persuasive their manager could be, especially when Keegan captained England in the 1980 European Championships in Italy.  Keegan had a clause inserted into his contract when he joined Hamburg in 1977, giving Liverpool the option to buy him back. Liverpool, however, opted not to exercise this clause when he returned to England three years later. As late as November 2011, Keegan has stated, "I was with Lawrie [McMenemy] at a charity event the other day, and he said he phoned up Peter Robinson because he wanted me, but Liverpool had a clause. Peter said, 'No, we won't be signing him, definitely, we don't need him.'" It was therefore Southampton boss Lawrie McMenemy who snapped him up for PS420,000, and Keegan made his Southampton debut at Lansdowne Road in a pre-season friendly against Shamrock Rovers on 23 July 1980.  Keegan's two seasons at The Dell saw him as part of a flamboyant team also containing Alan Ball, Phil Boyer, Mick Channon and Charlie George and in 1980-81 Saints scored 76 goals, finishing in sixth place, then their highest league finish.  In the following season, Keegan was able to produce some of his best form and at the end of January 1982 Southampton sat at the top of the First Division table, but a run of only three wins from the end of February meant a rather disappointing seventh-place finish. Despite this, Keegan was voted the PFA Player of the Year and awarded the OBE for services to Association Football. Keegan had scored 26 of the team's 72 goals and was voted the club's Player of the Year.  Keegan had fallen out with McMenemy over the manager's failure to strengthen Southampton's defence (which conceded 67 goals in 1981-82) while the team was at the top of the table. There were also rumours that McMenemy had charged the whole team of cheating after a 3-0 defeat by Aston Villa in April 1982 to which Keegan took great exception. Although Keegan joined Saints' next pre-season tour, he had already decided to move on to seek a new challenge, and a few days before the start of the 1982-83 season he signed for Second Division Newcastle United for a fee of PS100,000.  Keegan made his England debut on 15 November 1972 in a 1-0 World Cup qualifying win over Wales. Keegan appeared in only the two matches against Wales during this campaign as England failed to qualify for the 1974 FIFA World Cup.  He scored his first international goal in his third appearance, also against Wales, on 11 May 1974. He was given the captaincy by manager Don Revie in 1976 after Gerry Francis fell from favour. He went on to captain England 31 times, retaining the captain's armband until his international retirement after the 1982 World Cup.  Keegan captained England at the 1980 Euros. England failed to progress from the group stage after finishing third in their group behind Italy and Belgium.  He managed only one World Cup appearance though, after England failed to qualify for both the 1974 and 1978 tournaments. He finally reached a World Cup in 1982 when England got to the finals in Spain. He was duly named in the squad for the tournament but was suffering from a chronic back injury and was unfit to play in all of England's group games. In a last, desperate effort to play in a World Cup (he knew that he would not be around for the 1986 competition) he secretly hired a car and drove from Spain to a specialist he knew in Germany for intensive treatment. He recovered sufficiently to appear as a substitute for the last 26 minutes of England's final Second Round game against hosts Spain. Unfortunately, though, his brief experience of World Cup football saw him miss a point-blank header which would have broken the deadlock, in a game England needed to win to progress to the semi-finals. England drew the game 0-0 and were eliminated from the competition.  Following the successful start to the 1982-83 season with Newcastle United, there was much controversy when newly appointed England manager Bobby Robson did not select Keegan for his first squad, a decision Keegan learned of from the media rather than Robson himself. Keegan publicly expressed his displeasure at not being given the courtesy of a phonecall from Robson, and never played for his country again. He had won a total of 63 caps and scored 21 goals.

Where did he transfer from?