Monaco (CNN) -- A day after tying the knot in a civil ceremony, Monaco's ruler and his South African bride reaffirmed their union Saturday in a religious ceremony at the prince's palace.
The event kicked off the second day of festivities in the small seaside nation of 33,000, where a holiday has been declared to celebrate the wedding of Charlene Wittstock, a former Olympic swimmer, and Prince Albert.
The 3,500 guests -- which include 20 heads of state, fellow royals and a number of moguls and celebrities -- began to arrive hours earlier Saturday afternoon at the palace, the same place where one day earlier the couple's civil ceremony had taken place.
They walked through Palace Square into the courtyard, passing hundreds of onlookers who followed the nuptials on a pair of giant screens.
The last one to stroll the carpet, just before 5 p.m., was Wittstock herself. Her white wedding gown was designed by Giorgio Armani, according to the fashion designer's Facebook page.
Archbishop Bernard Barsi conducted the Roman Catholic ceremony under partly cloudy skies, with temperatures forecast to be around 80 degrees Fahrenheit.
"We ask God to bless you, to make your love strong and keep you in unity and loyalty," the archbishop said.
In matching vows, the couple promised to remain loyal to one another in sickness and in health, and then slipped wedding rings on each other's fingers.
Once the ceremony ended, the new princess left to leave her bouquet at the Sainte Devote church -- a Monaco tradition -- and join her new husband for a public procession through the city streets.
This will be followed by an official dinner crafted by celebrity chef Alain Ducasse and fireworks outside the Opera de Monte Carlo.
The event has galvanized the attention of thousands around the world, whose fascination with Monaco's royalty blossomed with the April 1956 wedding of Prince Ranier III and Hollywood movie star Grace Kelly.
Albert, 53, is that couple's only son, and they also had two daughters in Princesses Caroline and Stephanie. Prince Albert formally became Monaco's head of state following his father's death in 2005.
While he has publicly acknowledged he has fathered two children, this is his first marriage.
Also an Olympian, having competed in bobsled competitions in five Olympic Winter Games -- from Calgary in 1988 to Salt Lake City in 2002 -- the prince met Wittstock at a swimming event in Monaco in 2000. That summer, the 33-year-old woman swam for South Africa in the 2000 Sydney Olympics.
The couple announced their engagement last summer.
The couple's marriage became legal Friday, with a short civil ceremony at the palace. Afterwards, the couple and their guests feasted at a picnic and took in musical concert featuring Jean Michel Jarre.
The guest list for the two-day extravaganza includes heads of state, like French President Nicolas Sarkozy and Sweden's King Carl XVI Gustaf and Queen Silivia, and members of the rich and famous such as British model Naomi Campbell, British business mogul Richard Branson and Armani.
However, the United Kingdom's royal newlyweds -- Prince William and Catherine, Duchess of Cambridge -- missed the wedding as they are on an official tour of Canada.