Eagles' original lineup: Meisner, Henley, Frey, Leadon

Eagles co-founder Glenn Frey helped create the California rock sound of the 1970s by alternating between the gentility of folk music and harder-edge electric guitar riffs long associated with his hometown of Detroit.

Frey was a gifted guitarist who shared lead and rhythm duties, while his distinctive high tenor was the pleasant and comforting side of the Eagles vocals, a contrast to Don Henley's grittier Texas tone and the high-reaching vocals of Randy Meisner and his eventual replacement, Timothy B. Schmit. Frey's vocals shone on ballads, most notably “Lyin' Eyes” and “New Kid in Town,” uptempo rock material like “Already Gone” and “James Dean” and buoyant pop, a standout being “Heartache Tonight.”

His legacy, though, following his death on 1/18 at the age of 67, will be in the rich harmonies he created with Henley on Eagles songs such “After the Thrill is Gone,” “Take It Easy” and “Peaceful Easy Feeling,” many of them the result of Frey and Henley being perfectionists in the studio.

In early December, the Eagles postponed receiving their Kennedy Center Honor due to Frey's intestinal health issues, which had troubled him since the 1980s. Frey died in New York of rheumatoid arthritis, acute ulcerative colitis and pneumonia following intestinal surgery.

"The bond we forged 45 years ago was never broken, even during the 14 years that the Eagles were dissolved,” Henley said in a statement. “Glenn was the one who started it all. He was the spark plug, the man with the plan.

"He had an encyclopedic knowledge of popular music and a work ethic that wouldn’t quit. He was funny, bullheaded, mercurial, generous, deeply talented and driven… I'm not sure I believe in fate, but I know that crossing paths with Glenn Lewis Frey in 1970 changed my life forever, and it eventually had an impact on the lives of millions of other people all over the planet.”

A litany of fellow artists took to Twitter to offer thanks, expressions of grief and shock, among them Steve Martin, Natalie Maines, Tim McGraw, Brian Wilson, Ringo Starr, Meat Loaf, Magic Johnson and Toto's Steve Lukather.

Bette Midler, wrote that she loved the Eagles, explaining, “His songs, those sounds, perfectly captured those days. 70s LA.” Toby Keith chimed in with “Thank you for the songs and inspiration to so many. Missed by all.”

As a songwriter, Frey wrote two songs for their debut and co-wrote “Take It Easy” with Jackson Browne; on their second album, Desperado, he and Henley became a team, co-writing the title track, “Tequila Sunrise” and other songs. Together, and multiple times with another bandmate, they wrote many of the Eagles biggest hits: “Best of My Love,” “One of These Nights,” “Lyin' Eyes,” “Take It to the Limit,” “Hotel California,” “New Kid in Town,” “Life in the Fast Lane,” “The Long Run,” “I Can't Tell You Why” and “Heartache Tonight.”

At the premiere of the documentary The History of the Eagles at the Sundance Film Festival in 2013, Frey said, “We were a commercial band by the nature of our sound, and those were the days when you had hit singles and they went on AM radio and the album tracks, the unedited stuff, went on FM. It was as simple as that. We were sort of able to do both successfully.”

Prior to the Eagles, Frey performed with Bob Seger and, after moving to Los Angeles, formed Longbranch Pennywhistle with J.D. Souther, who would convince his girlfriend Linda Ronstadt to use Frey and Henley in her backing band. Breaking out on their own and calling themselves the Eagles, Frey, Henley, multi-instrumentalist Bernie Leadon and bass player Randy Meisner were building a buzz in Southern California when young hustler Irving Azoff became a fan—leaving his job at David Geffen and Elliot Roberts’ management company to become their manager, a role he’s played for 44 years.

“Honestly, for me, it was like seeing The Beatles—I thought it was that good,” Azoff recalled. “You know, my Midwest upbringing, the country-rock roots to it, those vocals—the haunting Henley vocal with the Frey kind of really dry country vocal—I thought they were equally just phenomenal. Funny thing, I always thought that when I first saw them, for me it was the Frey/Henley band. The hype in those days was that Randy Meisner came from Poco and Bernie Leadon came from the Flying Burrito Brothers. I went, ‘Hmm, sidemen.’”

The Eagles would win Grammys for “Lyin' Eyes,” “New Kid in Town” and “Heartache Tonight”; Hotel California won Record of the Year for 1977, would sell 16m copies and hit the Top 3 in 11 countries. Their Greatest Hits 1971-1975 has been certified platinum 29m times, making it the second biggest seller of all-time, behind only Michael Jackson's Thriller.

After the nine-year run that saw them become the biggest American band in the world, Frey got off to a fast start as a solo act, scoring hits with “Smuggler's Blues,” “The Heat Is On” and “You Belong to the City” while also embarking on an acting career. He largely stopped recording after his fourth album, 1992's Strange Weather, save for the Eagles’ 2007 Grammy-winning release Long Road Out of Eden and the 2012 solo album After Hours.

The Eagles Hell Freezes Over reunion tour of 1994-95 grossed $142.7m, and since then the band has been a consistent performer on the arena circuit worldwide. Their tour for Long Road Out of Eden of 2008-11 grossed a reported $251.1m. When the documentary was released and the band created a chronologically ordered show that included guest appearances from original member Bernie Leadon, they pulled in $145m between July 2013 and July 2104, playing to 1.1 million fans. That tour wrapped in July.

Still a quintessential Southern California band, the Eagles were the first to play the Forum when it reopened in January 2014, starting with a six-night stand and the first to christen downtown L.A.'s Nokia Theater in 2007, also with six shows.

Survived by his his wife, Cindy, and three children, Taylor, Deacon and Otis, Frey had largely assumed the roles of spokesman for the band and often did the bulk of the storytelling at their concerts. He lost patience, though, with the band's critics, who wanted to harp on the group's well-known personality clashes. At the band's induction into the Rock and Roll Hall of Fame in 1998, he told the Eagles critics to “get over it.”

“We got along fine,” he said, “we just disagreed a lot. Tell me one worthwhile relationship that has not had peaks and valleys.”

Frey, Azoff and Dan Fogelberg