Robert Emmanuel Pires (born 29 October 1973) is a former French footballer and footballing coach. Pires played for French clubs Metz and Marseille prior to his time with Arsenal, where he won three FA Cups and two Premier League titles including the club's unbeaten season of 2003-04. A former France international, Pires earned 79 caps between 1996 and 2004 for his country, including winning both the 1998 FIFA World Cup and UEFA Euro 2000. He has been included in the PFA Team of the Year for the 2001-02, 2002-03 and 2003-04 seasons, was the Player of the Tournament for the 2001 FIFA Confederations Cup, FWA Player of the Year for the 2001-02 season, Ligue 1 Young Player of the Year for the 1995-96 season, and was included in the FIFA 100 by Pele.

In May 2006, Pires agreed to join Spanish side Villarreal. He joined on a free transfer, subject to passing a medical, bringing to an end his six-year career as an Arsenal player. After Villarreal were eliminated in the semi-finals of the 2006 Champions League by Arsenal, Villarrael coach Manuel Pellegrini had wanted to sign Arsenal's Pires or Thierry Henry.  Pires was officially unveiled as a Villarreal player on 3 July 2006. He scored his first goal for the club in 3-3 pre-season draw with Newcastle United on 5 August 2006. However, on 18 August 2006, Pires damaged the cruciate ligament in his left knee in a friendly match against Cadiz and required corrective surgery to alleviate the problem, which kept him out of action for seven months in his new club in Spanish top flight. Pires finally recovered from knee injury and made his first league appearance for Villarreal as a second-half substitute when he was named in Villarreal's squad to face Real Sociedad on 17 March 2007. Pires scored his first league goal on his return from injury in a 3-3 draw away to Real Betis on 31 March 2007. After three appearances as a substitute, Pires made his first start for Villarreal on 22 April 2007 against Barcelona. He opened the scoring for his team to defeat league leaders Barcelona 2-0, avenging his premature departure against Barcelona in the Champions League Final the previous May. On 13 May 2007, in a thumping 4-1 win at Osasuna, the former France international midfielder gave the visitors the perfect start with a seventh-minute opener as Villarreal continued their late-season push for a European spot. The run took "The Yellow Submarine", sinking at 11th spot without him in the side, to the brink of a UEFA Cup place in barely six weeks. Villarreal ended the season in 5th spot wherein Pires played crucial roles in helping Villarreal with the late charge up winning each of their final eight games and an entry into the UEFA Cup.  The 2007-08 season was marked by the ongoing saga between Juan Roman Riquelme and the board of Villarreal. Despite this distraction, Pires' leadership qualities helped Villarreal to win six of their opening eight games. Against Barcelona at El Madrigal, Pires technique earned the Yellow Submarine two penalties which were duly converted by captain Marcos Senna. By contrast, Pires' former national and Arsenal teammate Thierry Henry struggled at Barcelona.[2] Villarreal ended up finishing second in La Liga behind Real Madrid, which was their best league finish in history, beating Barcelona into third place.  In 2009, Pires faced former club Arsenal in the quarter-finals of the UEFA Champions League, coming on as a 70th-minute substitute in the first leg and playing the full 90 minutes at the Emirates Stadium. Villarreal were defeated 4-1 on aggregate, but Pires received a warm return from the Arsenal supporters, who sang his name throughout both legs.  Pires was told in May 2010 that his contract would not be extended and he would have to look for a new club during the summer as Villarreal will be "changing their philosophy".

Answer the following question by taking a quote from the article: What is Villarreal?
In May 2006, Pires agreed to join Spanish side Villarreal.