Seoul: A South Korean court on Friday convicted Lee Jae-yong, the heir to the Samsung business empire, of bribery and embezzlement and sentenced him to five years in prison, in a dramatic break with the country's history of dealing light penalties to major business figures.

The verdict sends the strongest message yet to South Korea's big, family-controlled businesses that their more than 60 years of economic dominance in one of the world's most successful economies is under threat. Those companies helped build an economic powerhouse out of the ashes of the Korean War. Today, they are widely seen as sources of corruption and impediments to the country's progress.

It also presents new challenges for Samsung, a constellation of businesses so vast that it accounts for about one-fifth of South Korea's exports all by itself. The electronics company has argued that Lee provided long-term strategic vision and helped cement alliances with key partners like Apple and Google.

The court ruled that Lee and four other Samsung executives paid $6.4 million in bribes and other inducements to ensure that the country's disgraced former president, Park Geun-hye, supported a complicated corporate deal that strengthened Lee's grip on Samsung Electronics.