BANGKOK: Hundreds of orange-robed monks led ceremonies Thursday marking 70 years since Thailand’s King Bhumibol Adulyadej ascended to the throne following the mysterious death of his brother, as anxiety grows over the health of the ailing octogenarian. The 88-year-old king is the world’s longest serving monarch and is seen as a unifying force in a nation bitterly divided along political lines. But he is hospital-bound and underwent a heart operation on Tuesday, following months of treatment for various health problems — including water on the brain. His health is of grave concern to Thais, who revere the king and see him as a constant in a turbulent country that has seen numerous coups and repeated rounds of deadly political violence. Bhumibol’s image has been burnished by ritual and a publicity machine that sees giant portraits placed on streets and cinema-goers asked to stand for the royal anthem. The leading royals are also shielded from criticism by a harsh royal defamation law that carries up to 15 years in jail for each charge. The crown is also one of the world’s richest, with a multi-billion-dollar property and investment portfolio.