Islamic tradition | An ancient ceremony highlights the continued importance of religion in the country.

RIYADH, Saudi Arabia — From across the Arabian Peninsula, some traveling for two days, hundreds of Muslim clerics, princes, tribal chiefs and dignitaries crowded yesterday into a silk-carpeted palace here to pledge allegiance to Saudi Arabia's new monarch, in a traditional Islamic ceremony that sealed former Crown Prince Abdullah's status as the sixth king of the world's largest oil exporter.

Known as bayah, the ceremony is older than the kingdom itself, dating to the days of the Prophet Mohammed and the succession of caliphs that followed his death in the seventh century. In ritual and message, it was a reminder of the underpinnings of one of the world's wealthiest nations, a near-absolute monarchy that relies on religion for its legitimacy, sanctioned by the country's powerful clergy.

The ceremony was the last step in the scripted succession that followed King Fahd's death on Monday. It marked Abdullah's formal assumption of the power that he had exercised as crown prince in the decade since Fahd suffered a major stroke.

He promised to adhere to the Quran as the country's constitution and "serve all the people without discrimination."

"I appeal to you to support me and help me carry this trust and don't hesitate to advise me," he said.

The ceremony was a vivid reminder of how the ancient and modern converge in Saudi Arabia — especially in its capital, Riyadh, much of it a gleaming, Oz-like city that sprawls across a once-barren desert. At the palace and other royal residences, the diversity of Saudi Arabia gathered: men in uniforms, clerics in turbans, princes in pressed robes and tribal chiefs in checkered head scarves. In a sign of their import, the country's highest-ranking clergy were the first to pledge their allegiance; others waited hours, sometimes in vain.

The House of Saud has depended for legitimacy on the support of clerics from the kingdom's strict Wahhabi version of Islam since Abdullah's father, Abdul-Aziz bin Saud, welded the Arabian Peninsula tribes into a nation under his name in 1932.

Since Fahd's death, officials have rarely wavered from their theme: Continuity will mark the kingdom's policies. But Abdullah takes power at a time when his country is facing a threat by Islamic militants and a wary religious establishment uneasy at the kingdom's alliance with the United States. For others, expectations are high that the king will move ahead on political and economic reforms that he has until now only tentatively embraced.

The kingdom's coffers are overflowing with oil profits amid rising prices — spiking to $61 per barrel on news of Fahd's death. After years of deficits because of low oil prices, Abdullah now has cash to please disgruntled members of the royal family.

Additional background from The Associated Press