The Pro12 (known as the Guinness Pro12 for sponsorship reasons) (formerly known as the Celtic League, Magners League and RaboDirect Pro12) is an annual rugby union competition involving twelve professional sides from Ireland, Italy, Scotland and Wales. The league is one of the three major professional leagues in Europe (along with the English Premiership and the French Top 14) the most successful teams from which go forward to compete in the European Rugby Champions Cup, the pan European championship which replaced the Heineken Cup after the 2013–14 season.