Question: Which football team won a La Liga trophy in the season that started on 29 August 1998 and finished on 20 June 1999?

full_context: Document 1: 2007–08 FC Barcelona season: Though it did not produce silverware, Futbol Club Barcelona's 2007–08 season would mark a period of change within the club, having many firsts and lasts. Most importantly, this would be Ronaldinho's last season with the club, being displaced by the coming of Arsenal legend Thierry Henry. This season also marked the breakthrough of young talent Bojan into the first team, as well as the emergence of Lionel Messi as one of the team's key players. On the other hand, this would be Lilian Thuram's last season as a professional footballer, as well as Gianluca Zambrotta's last with the club.
Document 2: 2000–01 FC Barcelona season: Barcelona lost their supremacy of Spanish football, finishing just fourth in La Liga, despite having bought Marc Overmars and Emmanuel Petit in total of £54m transfer fee in the summer of 2000. While Barcelona was controversially sold Luís Figo to arch rivals Real Madrid in July 2000. New coach Lorenzo Serra Ferrer was not improved well and put under increasing pressure, and when Barcelona narrowly missed out on Champions League qualification in the summer, he was sacked in late April 2001. Barcelona dramatically sealed Champions League 3rd qualifying spot in the season finale, thanks to Rivaldo bicycle kick goal against Valencia.
Document 3: 1998–99 La Liga: The 1998–99 La Liga season, the 68th since its establishment, started on 29 August 1998 and finished on 20 June 1999.
Document 4: 1996–97 La Liga: The 1996–97 La Liga season, the 66th since its establishment, started on 31 August 1996 and finished on 23 June 1997.
Document 5: 2007–08 La Liga: The 2007–08 La Liga season, the 77th since its establishment, started on 25 August 2007 and finished on 18 May 2008. Real Madrid defended their La Liga title successfully after a 2–1 victory over Osasuna. This season, all European leagues ended earlier than the previous season, due to the UEFA Euro 2008 championship. It also was the first year of the new La Liga television agreement that had La Sexta mark its first year of television broadcasting.
Document 6: 2008–09 FC Barcelona season: In 2008–09, Futbol Club Barcelona started a new era with a new manager, former player and Barcelona Atlètic coach Pep Guardiola, who led the team to the first treble in Spanish football history. After selling off high-profiled players such as Deco and Ronaldinho, Barcelona played scintillating football throughout the season, winning the Copa del Rey, La Liga and the UEFA Champions League. This Barcelona squad is considered as one of the best in history.
Document 7: 2004–05 FC Barcelona season: The 2004-05 season saw Fútbol Club Barcelona end their six-year wait for the La Liga title, having not won the league or, indeed, any trophy since the 1998–99 season and thus La Liga trophy returned in Barcelona's trophy room. Having finished second in La Liga the previous season, Barcelona once again competed in the UEFA Champions League as well as the Copa del Rey. The squad was restructured significantly following the retirement of key players Luis Enrique and Marc Overmars, as well as the return of Edgar Davids to Juventus and first team regulars Patrick Kluivert and Phillip Cocu moving onto new clubs. Ronaldinho's and new signing Samuel Eto'o's performances won them places in FIFPro's XI of 2004–05. Ronaldinho was later named FIFA World Player of the Year for 2005 for the second time in succession and with the highest points total ever; Eto'o came third. This season was also notable for the debut of Lionel Messi.
Document 8: 2009–10 FC Barcelona season: In 2009–10, Futbol Club Barcelona started the new season with the prospect of winning six major competitions in the 2009–2010 season. They contested for the Supercopa de España, UEFA Super Cup, FIFA Club World Cup, Copa del Rey, La Liga, and the UEFA Champions League. During the summer transfer window, the club swapped their top league goal scorer during the treble season, Samuel Eto'o to Italy's Inter Milan in exchange for Zlatan Ibrahimović, along with €48 million, bringing the total to €69 million.
Document 9: 1999 Supercopa de España: The 1999 Supercopa de España was a Spanish football competition, played over two legs on 8 August and 15 August 1999. It was contested by Valencia CF, who were Spanish Cup winners in 1998–99, and FC Barcelona, who won the 1998–99 Spanish League.
Document 10: List of La Liga stadiums: Since the inception of La Liga in 1929, Spain's highest level of association football annual league tournament, 85 football stadiums have been used to host matches, with one more stadium set to host its first La Liga match in the 2016–17 season. The inaugural round of La Liga matches took place on 10 February 1929 with five clubs hosting the opening fixtures.
Document 11: 1998–99 FC Barcelona season: During the 1998–99 FC Barcelona season, the club once again retained the La Liga title, but eliminated by Valencia in the round of 16 of Copa del Rey. Barcelona enjoyed a great season with their new signings Ronald de Boer, Patrick Kluivert, Frank de Boer, Mauricio Pellegrino, Boudewijn Zenden and Phillip Cocu. Barcelona's league start was slower in early season but Barcelona turnaround to secure La Liga in late-May, but Barcelona crashed out of the UEFA Champions League, following an another lackluster performance in the First Group Phase.
Document 12: 2017–18 La Liga: The 2017–18 La Liga season, also known as La Liga Santander for sponsorship reasons, is the 87th since its establishment. The season began on 18 August 2017 and is scheduled to conclude on 20 May 2018. The fixtures of the 2017–18 season were released on 21 July 2017.
Document 13: 1998–99 2. Liga (Slovakia): The 1998–99 season of the Slovak Second Football League (also known as "2. liga") was the sixth season of the league since its establishment. It began on 1 August 1998 and ended on 13 June 1999.
Document 14: 1997–98 La Liga: The 1997–98 La Liga season, the 67th since its establishment, started on 30 August 1997 and finished on 16 May 1998. On 29 March 1998, Sporting Gijón drew 0-0 with Real Zaragoza while Racing Santander, who were 19th in the table at the time, lost by Athletic Bilbao 4-3, to make Sporting Gijón the first team in La Liga history to be relegated in March, ending the season with a League record low points tally of just 13.
Document 15: 2005–06 FC Barcelona season: The 2005–06 season was Futbol Club Barcelona's 107th season in existence and 77th consecutive season in the top flight of Spanish football, La Liga. It was manager Frank Rijkaard's third season in charge of the club, a season in which he managed to successfully retain the La Liga title, as well as winning the UEFA Champions League and Spanish Super Cup. The squad was largely unchanged from the previous season, with only two players – Santiago Ezquerro and Mark van Bommel – joining the club. Gerard left on a free transfer during the summer.
ground_truth: Fútbol Club Barcelona