Apple on Monday named longtime executive John Ternus as its next CEO, signaling a major leadership transition at one of the world’s most valuable companies as Tim Cook prepares to step aside after more than a decade at the helm.

The company said Ternus, Apple’s senior vice president of hardware engineering, will take over as CEO on Sept. 1. Cook, who has led Apple since 2011, will move into a new role as executive chairman of the board.