These songs were made famous by ABBA,

 a  Swedish pop/dance group active from 1972 until 1982.

They remain a fixture of radio play lists and are one of the world's best selling bands, having sold over 370 million records world wide; they still sell two to four million records a year.

 ABBA was also the first pop group from mainland Europe to enjoy consistent success in the charts of English-speaking countries, including the United Kingdom, the United States, Canada, Ireland, South Africa, Rhodesia, Australia and New Zealand.

Their enormous popularity subsequently opened the doors for other Continental European acts.

The music of ABBA has been re-arranged into the successful musical Mamma Mia! that has toured worldwide and had a movie version released in July 2008.