Title: 2011–12 Arsenal F.C. season
Content:  The 2011–12 season was Arsenal's 20th season in the Premier League, and also marked the club's 125th anniversary. In the Premier League, Arsenal struggled to recover from a poor start to the season. Though they did finish the season in the final qualification berth for the next season's UEFA Champions League. Arsenal's UEFA Champions League campaign once again proved unsuccessful, falling at the first hurdle in the knockout stage, with a 4–0 defeat at Milan ultimately proving fatal. Exiting the FA Cup at the fifth round stage at the hands of Sunderland, and the League Cup in the quarter-finals against Manchester City, the two domestic cups were also out of Arsenal's reach. Arsenal finished the season in third place after winning their last league match 3–2 against West Bromwich Albion on 13 May 2012. It was the first season since the invincibles in 2003–04 which Arsenal finished the top London club in the league, or in which Arsenal finished ahead of Chelsea.
Title: History of Arsenal F.C. (1966–present)
Content:  Little did they know it at the time, but the defeat to Leeds would be Arsenal's last in the League for over a year. 2003–04 was a record-breaking season for Arsenal, as they won the Premiership unbeaten (26 wins, 12 draws, 0 defeats), finishing a clear 11 points ahead of second-place Chelsea. They became only the second team to do so, the first having been Preston North End in 1888–89. Their rivals for the title gained revenge in other competitions – Arsenal were defeated in the Champions League quarter-finals and FA Cup semi-finals by Chelsea and Manchester United, respectively, in successive matches. Faced with the potential 
Title: 2003–04 FA Premier League
Content:  The 2003–04 FA Premier League (known as the FA Barclaycard Premiership for sponsorship reasons) was the 12th season of the Premier League. Arsenal were the champions and Chelsea, who had spent heavily throughout the season, were the runners up. Arsenal ended the season without a single defeat – the first team ever to do so in a 38-game league season and the second team overall (the first was Preston North End in 1889, 115 years earlier, during a 22-game league season).
Title: 2020–21 Arsenal F.C. season
Content:  The 2020–21 season was Arsenal's 29th season in the Premier League, their 101st consecutive season in the top flight of English football and their 104th season in the top flight overall. In addition to the domestic league, Arsenal participated in the FA Cup and participated in the EFL Cup. They also qualified for the UEFA Europa League for the fourth consecutive year. Arsenal kicked off the season by defeating league champions Liverpool in the FA Community Shield. Arsenal finished eighth in their Premier League season, and following eliminations from the FA Cup, the EFL Cup, and the UEFA Europa League, they failed to qualify for European competitions for the first time since the 1994–95 season.
Title: Football in England
Content:  higher than sixth in the Premier League since their 1995 title triumph. They endured a two-year exile from the Premier League after being relegated in 1999, and since their second relegation in 2012 they have still yet to gain promotion. Under Arsène Wenger, Arsenal have so far been Premier League champions three times; in 1998, 2002 and 2004. On the first two occasions, they completed the double of the league title and FA Cup, while on the third occasion they won the title without losing a single league game all season. Chelsea made history in 1997 when they won the FA 
Title: 2004–05 Arsenal F.C. season
Content:  Arsenal ended the previous season as league champions, becoming the first side since Preston North End 115 years earlier to do so undefeated. They completed their historic league campaign with 26 wins, 12 draws and 90 points. By the end of January 2004, Arsenal were still in the hunt for all four trophies, but suffered setbacks in each of the cup competitions; they were unable to retain the FA Cup, losing out to eventual winners Manchester United in the semi-finals and days later were knocked out of the UEFA Champions League by Chelsea in the quarter-finals. They exited the League Cup after a defeat to Middlesbrough in early February.
Title: 2017–18 Arsenal F.C. season
Content:  The 2017–18 season was Arsenal's 26th in the Premier League and 98th consecutive season in the top flight of English football. The club participated in the Premier League, the FA Cup (as holders), the EFL Cup, the FA Community Shield and the UEFA Europa League. This was the first season that Arsenal did not participate in the UEFA Champions League since 1997–98. It was the first time they had played in the UEFA Europa League since its rebranding, having last participated in the 1999–2000 UEFA Cup. A relatively poor season saw Arsenal fail to maintain a consistent challenge for Champions League qualification, with their away form being a major factor, only winning four away games in the league all season with 11 defeats, and they were, until the final game of the season, the only team in England's top 4 divisions to not get a point 
Title: 2014–15 Arsenal F.C. season
Content:  The 2014–15 season was Arsenal's 23rd season in the Premier League and 95th consecutive season in the top flight of English football. This season Arsenal participated in the Premier League, FA Cup, League Cup, Community Shield and the UEFA Champions League. In the League an inconsistent first half of the season ended any realistic hopes for the title as Arsenal only won two out of their first eight games, with numerous injuries to important players. At one stage, Arsenal were as low as eighth heading into early December. In the second half of the season their form recovered massively, which included an eight-game winning run between February and April. In Europe, despite being widely expected to reach the quarter-finals, being favourites in the Round of 16 tie against AS Monaco, Arsenal 
Title: 1999–2000 Arsenal F.C. season
Content:  Arsenal ended the previous season as runners-up to Manchester United in the Premier League. The club made an indifferent start to the campaign as reigning league champions and failed to progress past the group stages of the UEFA Champions League. After defeat to Aston Villa in December 1998, Arsenal embarked on a 19 match unbeaten run (21 in all competitions) to climb up the league table. The run in all competitions ended against Manchester United in a FA Cup semi-final replay. In April Arsenal moved to the top of the Premier League after beating Middlesbrough 6–1, albeit having played a match more 
Title: 2001–02 in English football
Content:  Arsenal won their second Premier League title in five seasons, as well as their second double in the same period, after a remarkable season in which they fought with the rest of the top six for the title right up until the final stages. They scored in every Premier League game, were unbeaten away from home, and finished the league season with 13 successive wins - and also had the satisfaction of clinching the title with a win over Manchester United at Old Trafford in their penultimate game. Liverpool's second-place finish was their highest for 11 years, ironically ending Manchester United's top-two run which had started after 

Question: when was the last time arsenal win premier league?
Answer: 2003–04.