Former Cambodian King Norodom Sihanouk died early Monday at the age of 89.

Cambodian Deputy Prime Minister Nhik Bun Chhay said Sihanouk died of a heart attack in Beijing where he had been staying since January for treatment for a heart problem.

Sihanouk took the throne in 1941 but lost power when the monarchy was abolished after a military coup in 1970.

He was in exile in China before returning to his country in 1975. After a series of tragic historical events in Cambodia, including the bloody mass killings by the Khmer Rouge, Sihanouk’s power as king was restored in 1993. He announced his abdication in 2004.