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.