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

Context articles: 2009–10 La Liga
1998–99 2. Liga (Slovakia)
2014–15 Valencia CF season
1997–98 La Liga
2004–05 FC Barcelona season
2007–08 La Liga
Lionel Messi
List of Spanish football champions
1998–99 La Liga
2011–12 Real Valladolid season

The 2009–10 La Liga season (known as the "Liga BBVA" for sponsorship reasons) was the 79th La Liga since its establishment.
 Barcelona were the defending champions, having won their 19th La Liga title in the previous season.
 The campaign began on 29 August 2009 ended on 16 May 2010 due to all top-flight European leagues ending earlier than the previous season because of 2010 FIFA World Cup.
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.
The 2014–15 Valencia CF season was the club's 95th season in its history and its 80th in La Liga.
 This was the first season since 1997–98 that Valencia would not compete in any European competition despite previous season's lowest position finish in six years.
 Having missed out on European competition, the team competed in La Liga and the Copa del Rey.
 In La Liga, they finished fourth, qualifying for the play-off round of the 2015–16 UEFA Champions League.
 In the Copa del Rey, Valencia lost to Espanyol in the round of 16.
 Dani Parejo was the club's top scorer in the league, with 12 goals, while Paco Alcácer was the club's top scorer overall, with 14 goals.
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.
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.
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.
Lionel Andrés "Leo" Messi (] ; born 24 June 1987) is an Argentine professional footballer who plays as a forward for Spanish club Barcelona and the Argentina national team.
 Often considered the best player in the world and regarded by many as the greatest of all time, Messi is the only player in history to win five FIFA Ballon d'Or awards, four of which he won consecutively, and a record-tying four European Golden Shoes.
 He has won 29 trophies with Barcelona, including eight La Liga titles, four UEFA Champions League titles, and five Copas del Rey.
 Both a prolific goalscorer and a creative playmaker, Messi holds the records for most official goals scored in La Liga (358), a La Liga season (50) and a club football season in Europe (73), a calendar year (91), as well as those for most assists made in La Liga (138) and the Copa América (11).
 He has scored over 600 senior career goals for club and country.
The Spanish football champions are the winners of the primary football competition in Spain, La Liga.
 The league is contested on a round robin basis and the championship awarded to the team that is top of the league at the end of the season.
 La Liga, first established in 1929, originally contained ten teams.
 Before La Liga's organization, the Copa del Rey—a regionalised cup competition—was effectively the national championship.
 La Liga is contested in by 20 teams; the three lowest-placed teams are relegated to the Segunda División and replaced by the top three teams in that division.
 Of the founding teams in La Liga, only Real Madrid, Barcelona and Athletic Bilbao have not been relegated.
 The league was cancelled between 1936 and 1939 because of the Spanish Civil War.
The 1998–99 La Liga season, the 68th since its establishment, started on 29 August 1998 and finished on 20 June 1999.
The 2011–12 Spanish football season is Real Valladolid's second season in the second level in Spanish football after being defeated 3–2 on aggregate against Elche in La Liga promotion play-off in June 2011.
 This season will be the 31st of Real Valladolid in the second level in Spanish football.
 The general coordinator during last season, Chuti Molina, left his work on 14 June, becoming Real Murcia general director.
 On 17 June, Real Valladolid made official Abel Resino's detachment as he did not renew his contract as team manager.
 On 4 July, Carlos Suárez announced he had bought 59% of the club shareholding, becoming shareholder of Real Valladolid, and therefore the owner of the entity.
 At the same time he confirmed that he will not step down as chairman and, from the next day, news about the sporting aspect will be known.
 Earlier on 6 July, the club became official the incorporation of the Serbian manager Miroslav Đukić for the next 3 seasons.
 During that day, it also was confirmed that José Antonio García Calvo, general director, left his work.
<br>Real Valladolid qualified in 3rd position in Segunda División, behind both Deportivo and Celta de Vigo, with 82 points.
 It was the first time in the history that any team with 80+ points wasn't directly promoted to La Liga.
 Deportivo de La Coruña beat Real Valladolid's points record, getting 91 points in the whole season.
 The record was established by José Luis Mendilibar's team in 2007 when Real Valladolid scored 88 points and were champions.
<br>The team had to play the Promotion play-off again, and got the promotion to 2012–13 La Liga by winning 3–0 on aggregate to Córdoba in the Semifinal and by 2–1 to AD Alcorcón in the Final.