Samsung Electronics chairman Lee Kun-hee, who transformed the company into a global tech giant, passed away at the age of 78 on Sunday, the company said. Under Lee’s leadership, Samsung grew to become the world’s largest producer of smartphones and memory chips. The tech giant’s overall turnover today is equivalent to one-fifth of South Korea’s GDP.

“It is with great sadness that we announce the passing of Kun-hee Lee, Chairman of Samsung Electronics,” the company said in a statement. “Chairman Lee was a true visionary who transformed Samsung into the world-leading innovator and industrial powerhouse from a local business. His legacy will be everlasting.”

Samsung is the biggest of the many family-controlled conglomerates – ‘chaebols’, that dominate business in South Korea. These companies helped transform the nation from its war-ravaged past to its current standing of being the world’s 12th largest economy.

Lee inherited the chairmanship of the Samsung group in 1987, from his father who began the company as an exporter of fish and fruits. By then it was already South Korea’s largest conglomerate, with a wide range of operations from consumer electronics to construction.

After Lee took on the chairmanship, Samsung transformed into a global tech giant, becoming the largest producer of smartphones and memory chips. Lee was known to lead a reclusive lifestyle, earning him the nickname – the Hermit King. Lee’s son, Samsung Electronics vice chairman Lee Jae-yong, has been at the managerial helm of the tech giant since 2014.