The man who helped breathe new life into the styling of Lincoln vehicles as brand design director has left the company.

David Woodhouse, who was also Ford’s director of global strategic design since 2017, has resigned from the U.S. automaker. His move leaves more questions than answers as it’s unclear why he left given the successful overhaul of Lincoln’s lineup.

In a private Facebook post seen by Autonews, Woodhouse calls it a “difficult decision,” especially given his personal investment in Lincoln. “Ending a long-standing relationship with a corporation is just like ending a personal relationship multiplied by the number of wonderful friends and colleagues,” the designer wrote without elaborating.

The Lincoln Motor Company confirmed the split via a spokeswoman who said Woodhouse “elected to leave the company.” However, she did not provide more details.

Woodhouse has been with Ford Motor Company since 1999 when he was appointed chief designer at Premier Automotive Group, which at the time was the division that included luxury brands such as Lincoln, Volvo, Jaguar, and Land Rover.

Following other design duties within Ford, he was named director of design at Lincoln from December 2013 and director of global strategic design at Ford from June 2017. The timing for the latter promotion coincides with Jim Hackett’s appointment as Ford CEO.

During his tenure at Lincoln, Woodhouse helped turn around the brand using new styling which adopts a philosophy the company labels “quiet flight.” Notable Lincoln designs in which Woodhouse was involved include the C Concept, Continental Concept, Mk9 Coupe and Aviator Concept. For Ford, he had a hand in the styling of the Shelby GR1, Airstream, and Reflex concept studies.