Swedish pop quartet ABBA has sold nearly 400 million albums throughout its 50-year history. Formed in the late ’60s, the first ABBA songs were written by Benny Andersson and Björn Ulvaeus, who met in 1966 before Anni-Frid Lyngstad (also known as Frida) and Agnetha Fältskog completed the lineup in 1969. Their name is an acronym of the first initial in each of their given names. They released eight albums from 1972 through 1981.