Red Bull abruptly fired longtime team principal Christian Horner on Wednesday, ending a 20-year stint that included eight Formula 1 drivers’ titles and recent turmoil that rocked the team on and off the track.

Red Bull did not give a reason for the decision in a statement Wednesday, but thanked Horner for his work and said he will “forever remain an important part of our team history.”

Laurent Mekies of sister team Racing Bulls will replace Horner in his role as team principal and chief executive of the Red Bull team.

“From my first race win, to four world championships, we have shared incredible successes. Winning memorable races and breaking countless records. Thank you for everything, Christian!” F1 champion Max Verstappen of Red Bull posted on social media.

Horner had been Red Bull team principal since it entered F1 as a full constructor in 2005. He had performed his team and media duties as normal throughout the British Grand Prix last week.