Greg Greeley, Amazon VP of Amazon Prime and delivery experience, is leaving the company after 18 years, he posted on LinkedIn last night. During his time at Amazon, he held a number of senior leadership positions. Greeley is credited for helping create Amazon Prime and previously built Amazon’s European business.

Greeley expressed his gratitude to the tens of thousands of team members he worked with during his time there. He also described what initially attracted him to Amazon, which was Amazon CEO Jeff Bezos’ “heartfelt” letter to shareholders in 1997.

“That letter described a unique approach for a public company, and the vision it contained was even more powerful than I fully understood at the time,” Greeley wrote. “With a relentless focus on customers and eight clearly defined long-term principles, it has been the foundation for a phenomenal business  and I truly believe, even now, it is still Day 1.”

Greeley’s departure comes shortly after he reportedly shifted some of his attention to Whole Foods, which suggested Amazon would make Prime a part of the Whole Foods customer rewards program. Last month, he also touted Prime and how the company continues to invest in the delivery product. It’s not clear what Greeley’s next move will be, but he said “the time has come” for him to “take on a different challenge.”

Featured Image: John Zeedick/AP