Who is the oldest member of the pop group ABBA?

Björn Kristian Ulvaeus (born 25 April 1945; credited as Björn Ulvæus) is a Swedish songwriter, producer, a former member of the Swedish musical group ABBA (1972–1982). Bjorn was the oldest member of the pop group ABBA.

Agnetha Åse Fältskog (born 5 April 1950) is a Swedish recording artist. She achieved success in Sweden after the release of her debut album Agnetha Fältskog in 1968, and reached international stardom as a member of the pop group ABBA.

Anni-Frid Synni (born 15 November 1945), widely known as Frida Lyngstad or by just the mononym Frida is a Swedish pop and jazz singer. She reached international stardom as a member of the pop group ABBA.

Göran Bror Benny Andersson (born 16 December 1946) is a Swedish musician, composer, member of the Swedish music group ABBA (1972–1982).