When was the song mamma Mia created?

Mamma Mia is the first track on the ABBA's third album (simply called ABBA). released on April 21, 1975. It was actually the last song recorded for the album and it was never intended to be a single. But a music video produced for the song (directed by future Oscar-nominee Lasse Halstrom), became a huge hit in Australia, prompting ABBA's record company Polar to release the single worldwide. Many people believe this was the first proven example of the potential of music video. (MTV was launched six years later.)