Thailand has crowned its new king in a three-day celebration that comes almost 69 years to the day since the last coronation. 

The coronation ceremony of 66-year-old King Maha Vajiralongkorn started on Saturday, with a purification ritual using water from all of Thailand's 76 provinces. 

He was then presented with a symbolic nine-tier umbrella, as part of a ceremony marking the moment he became a fully-fledged King.

Placing the crown on his head, King Vajiralongkorn delivered his first royal command on the throne.

"I shall continue, preserve, and build upon the royal legacy and shall reign with righteousness for the benefit and happiness of the people forever," he said. 

Many came to the Grand Palace to be part of the coronation ceremony. Wearing yellow, the color associated with the king, they hoped to catch a glimpse of the constitutional monarch who is revered in Thai culture as a living deity. 

The new King, like his predecessors, completed the first day of his coronation ceremony by announcing himself the protector and patron of Buddhism.

Chinese President Xi Jinping sent a congratulation message to King Vajiralongkorn on Saturday on his coronation, extending congratulations and good wishes to the king and the Thai people.

Read more:

President Xi congratulates Thai King Maha Vajiralongkorn on his coronation

The second day was highlighted by a grand procession. 

The royal parade covered seven kilometers from the Grand Palace to three royal temples, where the King paid his respects to Buddha. 

Tens of thousands of well-wishers gathered to witness the first coronation in nearly seven decades, a once-in-a-lifetime opportunity 

A well-wisher named Donnapha Kladbupha said, "This is the historic moment of the past 69 years. I feel like I need to be here to show the world how much we worship the King." 

Afterward, the newly-crowned King granted new titles to the members of the royal family.

But thousands still lined the streets well into the evening as lights lit the streets of Bangkok's old quarter. They were awaiting the King's first public appearance.

As the sun started to drop, the King emerged, carried aloft by an honor guard, flanked by soldiers in huge bearskin hats, and accompanied by a marching band and the hum of pipes.

On the third and final day, the King greeted well-wishers from the balcony of the Grand Palace and met foreign diplomats.

Monday has been declared a national holiday in Thailand to honor the newly-crowned King.