When Oscar-winning American actress Grace Kelly walked down the aisle to marry Prince Rainier of Monaco on April 19, 1956, two fairy-tale worlds converged.

Kelly, a Philadelphia heiress, married Rainier, scion of Europe's House of Grimaldi and its tiniest principality, in a grand ceremony that captivated the world.

Heads of state, royals, socialites and celebrities including David Niven, Cary Grant, Aristotle Onassis, Ava Gardner and the Aga Khan attended the solemn Roman Catholic ceremony, which transformed Kelly from one of the world's most beautiful starlets to a woman who bore the title Her Serene Highness.

Kelly's wedding dress was storied in its own right: Designed by MGM studio costume designer Helen Rose, it was fashioned from 125-year-old Valenciennes rose-point lace, silk taffeta and 98 yards of tulle.

The dress was a lavish gift from the movie studio, which came with some strings attached: Kelly was released from her film contract to attend to her new royal duties in exchange for the studio's rights to televise the service. (Kelly was said to have later regretted marrying under the glare of television lights.)

The 26-year-old Kelly had been dressed by Rose in films "High Society" and "The Swan."

The designer, who claimed it was the most elaborate piece she had ever created, worked with a team of more than a dozen seamstresses for six weeks to complete it.

Prince Rainier wore a Napoleonic-era-inspired military suit of his own design.

While regal, Kelly's much-copied wedding attire was designed with modesty in mind for a religious ceremony so pious that the prince and his princess-to-be were instructed by clerics not to look at each other during most of the service.

"From the crown-like wreath topping the headpiece to the bows down the back of the graceful train (Kelly's) wedding dress was simple but exquisitely detailed," according to the curator's notes of the Philadelphia Museum of Art, which keeps the dress in its permanent collection. Elaborate floral motifs in the lace were detached from their original base and sewn together again to follow the shape of the dress.

Brussels lace and lustrous seed pearls were used to unify the dress and Kelly's accessories, which included an embellished prayer book.

Rose also designed the equally discreet, but chic, lace suit Kelly wore for her civil marriage to the prince, a more relaxed, private ceremony before 80 family and friends that took place a day before the religious service.

Kelly's large coterie of bridesmaids wore floor-length dresses with sheer, full sleeves and brimmed hats. The dresses, designed by Joseph Hong of Neiman Marcus, elevated the profile of their seamstress, Priscilla Kidder of the bridal atelier Priscilla of Boston. The maids carried bouquets of tea roses, while Kelly's flower girls held daisies.

Besides her 10-carat square-cut diamond engagement ring set in platinum with two adjoining diamonds, Kelly received a treasure trove of Van Cleef & Arpels jewels from her husband as wedding gifts.

The dashing prince, who had been known as a European playboy before meeting Kelly at a photo shoot in Cannes, France, commissioned the House of Creed to concoct Fleurissimo, a signature perfume inspired by his bride to honor the state occasion.

After the service, the couple cruised the streets of the resort nation in a black-and-cream Rolls Royce that was a gift from Monaco's 3,000 residents. In turn, the newlyweds invited all of its citizenry to celebrate at an outdoor party.

Monaco has another royal wedding on its horizon. Read about the wedding plans of the late royals' son, Prince Albert, to South African beauty and Kelly look-alike Charlene Wittstock. (And read about Wittstock's ambivalence about her role as a fashion icon.)

You can also read the first in our "Great Royal Weddings" series, about the marriage of Queen Elizabeth II and Prince Philip. For more news, including updates on the engagement and wedding plans of Prince William and Kate Middleton, visit royalwedding.aol.com.

(But click here for royal weddings that didn't end happily ever after.)