Danny Kirwan, the guitarist who made Fleetwood Mac a unique three-guitar force in the late 1960s andwhose songwriting guided the band as it transitioned over the course of five albums, died Friday in London. He was 68.

Mick Fleetwood confirmed Kirwan’s death in a post on Facebook, writing, “Danny was a huge force in our early years. His love for the blues led him to being asked to join Fleetwood Mac in 1968, where he made his musical home for many years.

“Danny’s true legacy, in my mind, will forever live on in the music he wrote and played so beautifully as a part of the foundation of Fleetwood Mac, that has now endured for over 50 years.” Kirwan was 18 when he joined guitarists Peter Green and Jeremy Spencer on Fleetwood Mac’s front line, his earliest appearances coming on the instrumental “Albatross,” a#1 hit in the U.K., and “Oh Well,” their first U.S. release and a #2 U.K. hit.

Green had discovered Kirwan in a club and, after jamming with him, attempted to help him put together a new blues rock ensemble. When that effort he failed, he asked Kirwan to join Fleetwood Mac despite objections from other members.

Kirwan joined Green as the band’s main songwriters, and he wrote five songs that appeared on their 1969 release Then Play On. Kirwan, who relished rehearsal and proper execution, and Green, the group’s brilliant improviser, had only one joint credit, though—"World in Harmony," the B-side of "The Green Manalishi."

Green left the band in 1970 and Spencer, a slide guitar player, pushed the group toward more of a vintage rock ‘n’ roll sound on Kiln House, where Kirwan took a more prominent role as the group’s lead guitarist. The followup, Future Games, saw the arrival of Christine McVie and Bob Welch replacing Spencer, which found the bâ€‹and adding softer elements from folk and pop.

Kirwan’s final album with Fleetwood Mac was Bare Trees in 1972, an album that showcased the pop direction the band would ultimately take in immediate future with more new members. While the album’s best known songs, “Sentimental Lady” and “Spare Me a Little of Your Love,” come from Welch and McVie, respectively, Kirwan wrote half the album’s songs, including the title track.

After smashing a guitar before a performance and refusing to go onstage Fleetwood and bassist John McVie fired Kirwan in 1972. He made three solo albums in the 1970s, none of which performed well commercially, and stopped playing live. Then, much like Green and Spencer had done, disappeared from the music scene. Unlike Green and Spencer, though, he never resurfaced.

While he was included as a member of Fleetwood Mac when they were inducted into the Rock and Roll Hall of Fame in 1998, he did not attend the ceremony.