Apple has entered a new era as Tim Cook officially steps down as CEO, with John Ternus taking over as the company’s new chief executive. Cook had been with Apple since 1998 and became CEO in 2011, following Steve Jobs’ resignation due to health issues.

The iPhone 5, 5s and 5c were the last iPhone models developed with significant oversight from Jobs. Although Jobs passed away shortly after the iPhone 4s was introduced, he still had an influence on the development of the iPhone 5 series. Every major Apple product since then has been developed under Cook’s leadership.

Before becoming CEO, Ternus served as Apple’s Senior Vice President of Hardware Engineering. He was responsible for the company’s hardware engineering teams covering the iPhone, iPad, Mac, Apple Watch, AirPods, Apple Vision Pro and other products.

Ternus therefore brings a strong hardware background to the CEO position, something that could prove important for Apple as it continues developing its major product lines. He has been associated with products including AirPods, the iPhone Air and MacBook Neo.

Cook will not be leaving Apple entirely, however. He will remain with the company as executive chairman, continuing his involvement with Apple after 15 years as CEO.

Before leaving the CEO position, Cook shared a message with Apple’s community, saying that while his title would change, his appreciation for the company and its community would remain unchanged. He also described the transition as the beginning of an exciting new chapter.