Question: When was the last time Arsenal's greatest rival won a trophy?

full_context: Document 1: Arsenal F.C.: Arsenal finished in either first or second place in the league in eight of Wenger's first eleven seasons at the club, although on no occasion were they able to retain the title. As of July 2013, they were one of only five teams, the others being Manchester United, Blackburn Rovers, Chelsea, and Manchester City, to have won the Premier League since its formation in 1992. Arsenal had never progressed beyond the quarter-finals of the Champions League until 2005–06; in that season they became the first club from London in the competition's fifty-year history to reach the final, in which they were beaten 2–1 by Barcelona. In July 2006, they moved into the Emirates Stadium, after 93 years at Highbury.
Document 2: Arsenal F.C.: In 1886, Woolwich munitions workers founded the club as Dial Square. In 1913, the club crossed the city to Arsenal Stadium in Highbury, becoming close neighbours of Tottenham Hotspur, and creating the North London derby. In 2006, they moved to the nearby Emirates Stadium. In terms of revenue, Arsenal is the ninth highest-earning football club in the world, earned €487.6m in 2016–17 season. Based on social media activity from 2014 to 2015, Arsenal's fanbase is the fifth largest in the world. In 2018, Forbes estimated the club was the third most valuable in England, with the club being worth $2.24 billion.
Document 3: Tottenham Hotspur F.C.: Spurs were one of the five clubs that pushed for the founding of the Premier League, created with the approval of The Football Association, replacing the Football League First Division as the highest division of English football. Despite a succession of managers and players such as Teddy Sheringham, Jürgen Klinsmann and David Ginola, for a long period in the Premier League until the late 2000s, Spurs finished mid-table most seasons with few trophies won. They won the League Cup in 1999 under George Graham, and again in 2008 under Juande Ramos. Performance improved under Harry Redknapp with players such as Gareth Bale and Luka Modrić, and the club finished in the top five in the early 2010s.
Document 4: Arsenal F.C.: Arsenal fans often refer to themselves as "Gooners", the name derived from the team's nickname, "The Gunners". The fanbase is large and generally loyal, and virtually all home matches sell out; in 2007–08 Arsenal had the second-highest average League attendance for an English club (60,070, which was 99.5% of available capacity), and, as of 2015, the third-highest all-time average attendance. Arsenal have the seventh highest average attendance of European football clubs only behind Borussia Dortmund, FC Barcelona, Manchester United, Real Madrid, Bayern Munich, and Schalke. The club's location, adjoining wealthy areas such as Canonbury and Barnsbury, mixed areas such as Islington, Holloway, Highbury, and the adjacent London Borough of Camden, and largely working-class areas such as Finsbury Park and Stoke Newington, has meant that Arsenal's supporters have come from a variety of social classes.
Document 5: FA Cup: Winners receive the FA Cup trophy, of which there have been two designs and five actual cups; the latest is a 2014 replica of the second design, introduced in 1911. Winners also qualify for European football and a place in the FA Community Shield match. Arsenal are the current holders, having beaten Aston Villa 4–0 in the 2015 final to win the cup for the second year in a row. It was their 12th FA Cup title overall, making Arsenal the FA Cup's most successful club ahead of Manchester United on 11.
Document 6: Arsenal F.C.: In 1886, Woolwich munitions workers founded the club as Dial Square. In 1913, the club crossed the city to Arsenal Stadium in Highbury. They became Tottenham Hotspur's nearest club, commencing the North London derby. In 2006, they moved to the Emirates Stadium in nearby Holloway. Arsenal earned €435.5m in 2014–15, with the Emirates Stadium generating the highest revenue in world football. Based on social media activity from 2014–15, Arsenal's fanbase is the fifth largest in the world. Forbes estimates the club was worth $1.3 billion in 2015.
Document 7: Arsenal F.C.: Arsenal's tally of 13 League Championships is the third highest in English football, after Manchester United (20) and Liverpool (18), and they were the first club to reach a seventh and an eighth League Championship. As of May 2016, they are one of only six teams, the others being Manchester United, Blackburn Rovers, Chelsea, Manchester City and Leicester City, to have won the Premier League since its formation in 1992.
Document 8: Tottenham Hotspur F.C.: Anglo - Italian League Cup: Winners (1): 1971 Costa Del Sol Tournament: Winners (2): 1965, 1966 Nolia Cup: Winners (1): 1977 Kirin Cup: Winners (1): 1979 Sun International Challenge Trophy: Winners (1): 1983 Peace Cup: Winners (1): 2005 Vodacom Challenge: Winners (2): 2007, 2011 Feyenoord Jubileum Tournament: Winners (1): 2008 Barclays Asia Trophy: Winners (1): 2009 AIA Cup: Winners (1): 2015
Document 9: Arsenal F.C.: Arsenal's longest-running and deepest rivalry is with their nearest major neighbours, Tottenham Hotspur; matches between the two are referred to as North London derbies. Other rivalries within London include those with Chelsea, Fulham and West Ham United. In addition, Arsenal and Manchester United developed a strong on-pitch rivalry in the late 1980s, which intensified in recent years when both clubs were competing for the Premier League title – so much so that a 2003 online poll by the Football Fans Census listed Manchester United as Arsenal's biggest rivals, followed by Tottenham and Chelsea. A 2008 poll listed the Tottenham rivalry as more important.
Document 10: List of football clubs in England by competitive honours won: England's first football competition, the FA Cup, began in the 1871 -- 72 season, making it the oldest football competition in the world. Arsenal hold the record number of wins, with 13. League football began in the next decade with the founding of The Football League in 1888 -- 89. The name First Division was adopted in 1892, when The Football League gained a second division. The First Division remained the highest division of the English football league system until 1992, when the Premier League was founded. Manchester United have won the most top division titles, with 20. The English equivalent of the super cup began in 1898 with the inauguration of the Sheriff of London Charity Shield, pitting the best professional and amateur sides of the year against each other. The trophy would develop into the FA Charity Shield in 1908, which was later renamed the FA Community Shield in 2002. Manchester United hold the record in the competition with 21 wins. The Football League created its own knockout competition in 1960, the League Cup. The Anglo - Italian League Cup was created in 1969 to match English cup winners against the winners of the Coppa Italia, and was permanently disbanded in 1976. In 1985, the Full Members Cup and Football League Super Cup were created as substitutes for UEFA competitions after UEFA responded to the Heysel Stadium disaster by banning English clubs. They finished in 1986 and 1992 respectively. The Football League Centenary Trophy marked The Football League's 100th birthday, in the 1988 -- 89 season.
Document 11: North London derby: As of 20 August 2017, there have been 180 competitive first - class meetings between the two teams since the first league meeting in 1909, of which Arsenal have won 75 and Tottenham 56. The most goals in one game were scored in the closely contested 5 -- 4 Arsenal Premiership victory at White Hart Lane on 13 November 2004. The biggest winning margin was a 6 -- 0 away win by Arsenal on 6 March 1935. Tottenham have twice won 5 -- 0 (25 December 1911 and 4 April 1983) and Arsenal once (23 December 1978), with all three fixtures taking place at White Hart Lane. Arsenal also won by 5 - 2 margins both in February and November of 2012 home at the Emirates.
Document 12: Arsenal F.C.: They hold the highest number of FA Cup trophies, with 13. The club is one of only six clubs to have won the FA Cup twice in succession, in 2002 and 2003, and 2014 and 2015. Arsenal have achieved three League and FA Cup ``Doubles ''(in 1971, 1998 and 2002), a feat only previously achieved by Manchester United (in 1994, 1996 and 1999). They were the first side in English football to complete the FA Cup and League Cup double, in 1993. Arsenal were also the first London club to reach the final of the UEFA Champions League, in 2006, losing the final 2 -- 1 to Barcelona.
Document 13: Manchester United F.C. in European football: The competition in which the club has had the most success is the European Cup (now known as the UEFA Champions League); they have won three European Cups, the first of which came in 1968; this win made them the first English club to win the European Cup. The other two victories came in 1999 and 2008. The club has also won the Cup Winners' Cup, which they won in 1991; the Super Cup, also won in 1991; the Intercontinental Cup, which they won in 1999; and the Europa League, which they won in 2017.
Document 14: FA Cup: Since the creation of the Football League in 1888, the final has never been contested by two teams from outside the top division, and there have only been eight winners who were not in the top flight: Notts County (1894); Tottenham Hotspur (1901); Wolverhampton Wanderers (1908); Barnsley (1912); West Bromwich Albion (1931); Sunderland (1973), Southampton (1976) and West Ham United (1980). With the exception of Tottenham, these clubs were all playing in the second tier (the old Second Division) -- Tottenham were playing in the Southern League and were only elected to the Football League in 1908, meaning they are the only non-League winners of the FA Cup since the League's creation. Other than Tottenham's victory, only 24 finalists have come from outside English football's top tier, with a record of 7 wins and 17 runners - up: and none at all from the third tier or lower, Southampton (1902, then in the Southern League) being the last finalist from outside the top two tiers.
Document 15: FA Cup: Winners receive the FA Cup trophy, of which there have been two designs and five actual cups; the latest is a 2014 replica of the second design, introduced in 1911. Winners also qualify for the Europa League and a place in the FA Community Shield match. Arsenal are the current holders, having beaten Chelsea 2 -- 1 in the 2017 final to win the cup for the 13th time in their history and become the tournament's most successful club. Arsenal's Arsène Wenger is the most successful manager in the competition with seven finals won.
ground_truth: 2015
sub_queries: What football club is Arsenal's greatest rival? Answer: Tottenham Hotspur
when was the last time Tottenham Hotspur won a trophy Answer: 2015