In June 1966, two of the biggest bands in Sweden, The Hootenanny Singers and The Hep Stars, crossed paths for the first time with gigs at the same venue. As the night's partying stretched to dawn, Björn Ulvaeus and his new Hep Stars friend, Benny Andersson, sang together in a park and agreed to meet for future collaborations.

As recalled in Bright Lights, Dark Shadows: The Real Story of ABBA, they joined up again a few weeks later and with Andersson on his organ and Ulvaeus on guitar, they worked out the melody for their first song. Later that year, The Hep Stars' self-titled album featured the fruits of their labor, the track "It Isn't Easy to Say," as well as a recording of the Ulvaeus-penned "No Time."

The convergence of the musical minds came as each was realizing the limitations of his current act. Ulvaeus, who came of age with the traditional Swedish folk ballads of The Hootenanny Singers, was now thinking about the pop music triumphs of The Beatles and had taken to shadowing his group's primary songwriter and producer, Stig Anderson, around the studio.

And Andersson, the lone songwriter of a group that had found success via the English-language pop that Ulvaeus admired, was also seeking an outlet for his creative inspirations, particularly as The Hep Stars' immersion into the cabaret circuit was creating an unbridgeable internal rift.

ABBA circe 1970

ABBA, circa 1970

The men entered relationships with future bandmates Frida Lyngstad and Agnetha Fältskog

In 1969, Andersson entered the Swedish trials of the popular Eurovision Song Contest. Although his song just missed out on winning and advancing to the international finals, the experience presented an opportunity to meet another contestant, Anni-Frid "Frida" Lyngstad.

Hailing from a jazz background, Lyngstad had competed in numerous talent contests over the years and was then performing in a cabaret act. Shortly after the Eurovision trials, she ran into Andersson and Ulvaeus at a restaurant, and after the three met up to appear on a radio program, she struck up a relationship with the free-spirited Hep Star.

Meanwhile, Ulvaeus had already met his future ABBA soulmate. At just 17, Agnetha Fältskog had captured Swedish audiences with a breakout single in early 1968, resulting in her collaborations and engagement to a West German songwriter-producer. However, her music failed to catch fire outside of Sweden, further complicating a relationship already strained by distance.

When Ulvaeus and Fältskog reunited in May 1969 for a TV special featuring several Swedish pop stars, the latter was again single and the former was determined to take advantage of their proximity, and they became an item again before the production concluded.

An early collaboration resulted in an unsuccessful cabaret act

By the end of 1969, The Hep Stars had disbanded, and The Hootenanny Singers were through as a performing act (though they would continue with studio work), freeing Ulvaeus and Andersson to focus on their work as songwriters and producers. Andersson took to nursing along Lyngstad's fledging career, though Ulvaeus initially resisted getting involved professionally with his significant other.

In April 1970, all four took off for a holiday in Cyprus. Along with serving as the occasion for Ulvaeus and Fältskog's engagement, it marked the first time they realized the magic of harmonizing together, their collective hunch confirmed with a spontaneous performance for U.N. soldiers stationed on the island.

That summer, Ulvaeus and Andersson focused on creating an English-language record, with Lyngstad and Fältskog on backing vocals. The finished product, Lycka, was uneven, though it produced a hit with the single "Hej Gamle Man!"

In November, the four launched the cabaret act Festfolk, a title that carried the double meaning of "party people" and "engaged couples." Festfolk flopped, as the quartet lacked the chops to pull off the comedic elements of the show, though their performance of "Hej Gamle Man!" always drew a favorable response.

ABBA posing at Waterloo railway station.

(L-R) Benny Andersson, Anni-Frid Lyngstad, Agnetha Faltskog and Bjorn Ulvaeus of ABBA posing at Waterloo railway station in 1974.

The group found their name and hit sound with "Ring-Ring" and "Waterloo"

Following a period of intermittent successes – Ulvaeus and Andersson had a surprise hit in Japan with "She's My Kind of Girl", while Lyngstad and Fältskog enjoyed starring roles in stage productions – the four convened in spring 1972 to record their first single, "People Need Love," under the group name Björn & Benny, Agnetha & Anni-Frid.

The foursome then teamed with Anderson to deliver a song for the 1973 Eurovision contest. The Anderson/Andersson/Ulvaeus-penned "Ring-Ring," completed with engineer Michael B. Tretow's innovative sound mixing, was the sort of catchy, upbeat track that would become a hallmark of the band's sound. To the surprise of many, "Ring-Ring" didn't win the Swedish trials, though it did become a major hit for the quartet and the title track for their debut album.

Meanwhile, Anderson was tired of the band's cumbersome title. Playing around with their initials, he came up with ABBA, a name that could easily overcome the obstacles of foreign-language branding. It also happened to be the name of a Swedish canned fish company, and while the company gave its approval, it took a little longer for the band to accept their association with canned fish.

The first records credited to ABBA surfaced in October 1973, though the band's complete transformation wouldn't come until the launch of the 1974 Eurovision contest. This time, clad in their glam rock finest as they performed the irresistibly catchy "Waterloo," the Swedish quartet blew away the competition with their look and sound, walking away with a contest victory and a smash record that announced their arrival as international pop stars.