Walter Parazaider, a co-founding member of Chicago who was with the band from its start in 1967 through his retirement in 2017, died Wednesday, family members announced. He had been suffering from Alzheimer’s disease for six years.

Parazaider played reed instruments in the band for that 50-year run, and may be most easily recognized for his flute solo in “Colour My World,” though he was more often found on the saxophone. In the band’s earliest conception, he was the only horn player, and he is often credited as the one whose idea it was to bring an entire horn section in as full members of a rock band, a radical idea when Chicago Transit Authority was being founded in ’67, and still a rare concept to this day.

His daughter, Felicia Parazaider, reported the death in a Facebook post in the early morning hours Wednesday. “I didn’t get back in time. My father, my hero, is gone. He went peacefully about 20 minutes ago,” wrote the daughter, a minister and “radical sacred activist.” “There’s no more pain. No more struggle. I psychically knew I wasn’t going to make it back in time. And I knew that it would be just my mom and him. It’s how it was in the beginning. Just the two of them. And so it should’ve been in the end. Thank you for loving my father, even if you didn’t personally know him. I know that many of you loved him. I’m in shock and disbelief and yet not at all. This was the worst six years. The hardest season of my life. And I’m so grateful that my dad is not suffering anymore. I love you poppy, my Pal. You coloured our world. God bless you, you dear soul. I love you beyond thoughts and words.”