12/03/2005 AT 09:40 PM EST
12/02/2005 AT 08:00 AM EST
Greek billionaire Athina Roussel Onassis, 20, granddaughter and sole heiress of the late shipping magnate (and onetime husband of Jacqueline Kennedy) Aristotle Onassis, and Brazilian equestrian star Alvaro Affonso de Miranda, the 32-year-old son of an insurance company owner, wed Saturday night in Brazil.
This was no ordinary ceremony, held at the Maria Luiza and Oscar Americano Foundation, an 18.5-acre spread that includes a museum, a tea house and a cultural center.
The wedding was a "family affair" attended by some 1000 guests, according to the groom's father, Ricardo Miranda. At least 400 private security guards were deployed to protect the guests and keep out paparazzi.
The bride, who was raised in Switzerland by her French-born father, Thierry Roussel, and inherited an estimated $2.7 billion from her grandfather on her 18th birthday, was to wear a dress by Valentino, the elder Miranda said.
The marriage was planned as an ecumenical ceremony, because Onassis is Greek Orthodox and the groom is a divorced Roman Catholic. The couple – who share a love for horses and met in 2002 at a riding center in Belgium – reportedly signed a prenuptial agreement protecting all assets acquired before marriage.
Already they share a $7.2 million, 10,650-sq.-ft. apartment in Sao Paulo with Viviane, Miranda's 6-year-old daughter from his previous marriage.
In lieu of wedding presents, the couple reportedly asked that guests donate money to the Aconchego Day Care Center for underprivileged children.