The lavish wedding of the heir to oil-rich Brunei's throne this week underscores the enduring importance of royal families in some Asian countries despite rapid modernisation.
Crown Prince Al-Muhtadee Billah Bolkiah, 30, son of Sultan Hassanal Bolkiah - once reputed to be the world's richest person - will marry commoner Sarah Salleh, 17, on Thursday in Asia's grandest wedding in years.
Bahrain's King Hamad, Japan's Crown Prince Naruhito and other royals will join an impressive array of heads of government from Brunei's immediate neighbours at the wedding, which is to be followed by a banquet on Friday.
The guest list includes Philippine President Gloria Arroyo, Indonesian President Megawati Sukarnoputri, Thai Prime Minister Thaksin Shinawatra, Singapore Prime Minister Lee Hsien Loong and Malaysian Prime Minister Abdullah Ahmad Badawi.
Preparations are in high gear, with streets and business establishments in this usually sleepy capital bedecked with banners and billboards wishing divine blessings to the couple.
In Brunei, Japan, Thailand and the tiny Himalayan Kingdom of Bhutan, monarchies dating back hundreds of years play unifying roles in society and serve as a ballast for political stability.
But elsewhere in Asia, monarchies have been sidelined to ceremonial roles or threatened with oblivion, and analysts warn those still in positions of power or influence must adapt to the forces of change in order to stay relevant in the long term.
Beyond the pageantry and symbolism, some modern royal houses play a crucial role in their societies, including in political systems where the democratic process can lead to bitter divisions.
"Depending on the political and socio-cultural context they are functioning in, monarchies have vital roles to play," said K. Kesavapany, director of the Singapore-based Institute of Southeast Asian Studies.
"His Majesty the King of Thailand is perhaps the exemplar of this point. Another would be the Emperor of Japan. The Sultan of Brunei has kept his country stable and his people basically satisfied," he told AFP.
Kesavapany however said that like other social institutions, monarchies must "adapt themselves to the forces of globalisation" to avoid being "swept away by the winds of change."
In Malaysia, royalty has become largely ceremonial after former prime minister Mahathir Mohamad curtailed their influence during his 22-year rule.
Real power now rests with elected leaders, but the monarchy has endured as the symbol of Malay culture and Islam.
Malaysia today has its own version of a constitutional monarchy where a king, who serves as the head of state, is elected from among the country's nine sultans every five years on a rotating basis.
"Our stubbornly cherished system of monarchy must seem to outsiders as nothing but a curious survival, an anachronism and one surely rendered obsolete now that we are in the third millennium," said Nazrin Shah, the crown prince of Malaysia's Perak state.
"This is to overlook the essentially dynamic process whereby the monarchy evolves, recreates and constantly redefines itself in tandem with the progress of society as a whole," he said in a recent lecture in Singapore.
To Malaysia's multi-ethnic society of Malays, Chinese and Indians, the monarchy is "a kind of invisible social glue", said Nazrin, who has a degree in philosophy, politics and economics from Oxford and a doctorate in political economy and government from Harvard.
But he agreed royalty must remain relevant by playing an active role in promoting social cohesion, reaching out to younger citizens who have few memories of the past, adapting to change and listening to the people.
Today's technology-savvy generation has "scant regard for, or patience with, grandeur and nostalgia," he cautioned.
In a sign of easing up, Brunei's Sultan Hassanal, whose dynasty dates back to 1371, announced in July his country will reconvene parliament for the first time in decades as part of political reforms.
Thailand's monarchy was founded in the 13th century with the Sukhothai dynasty. The kingdom became a constitutional monarchy in 1932.
The current King Bhumibol Adulyadej is the world's longest-serving monarch.
He ascended to the throne in June 1946 and has become a potent moral force.
He is Thailand's chief of state, and while day-to-day power rests with the government King Bhumibol exerts an almost supernatural hold over his people.
Despite carving out a position of strict neutrality in politics, the king has intervened several times in public life.
In Japan, the imperial family, which traces its origins to the sixth or seventh century, has been stripped of all political powers since the end of World War II.
The emperor, designated as "the symbol of the state" in the post-war constitution, merely receives foreign guests, awards honours and carries out other formalities.
But public loyalty to the imperial family appears unchanged especially among elderly people.
In Cambodia, King Sihanouk has been largely marginalised in the country's violence-riddled politics.
In Bhutan, King Jigme Singye Wangchuk, who ascended the throne at age 17 in 1972, has the unlikely role of trying to persuade his subjects to give him fewer powers after saying he no longer wanted to be an absolute monarch.
Known as the Druk Gyalpo, or "Dragon King," the king has used his considerable moral influence to champion causes such as preserving the self-isolated mountain state's culture and protecting the rights of HIV patients.
Nepal's monarchy has transformed in recent years from a unifying to an increasingly divisive institution.
In 2001, the drunken crown prince massacred nine members of the royal family including his parents before killing himself.
The new king, Gyanendra, has steadily boosted the power of the palace, dismissing the elected government in 2002.
Maoist rebels, who claim to fight on behalf of the impoverished majority, depict the king as a symbol of corruption and elitism and vow to abolish the monarchy if they come to power, but Hindu traditionalists revere the king as a god.