sentences:  The most successful teams are Cardiff City, Swansea City, Newport County, Wrexham and The New Saints.Cardiff City were the most successful in the 20th century, having won the FA Cup in 1927 and spent 15 seasons in the top-flight English First Division.Swansea City have also played in the top flight, playing two consecutive seasons in the early 1980s, and were the first Welsh team to win promotion to the English Premier League in 2011.