Greek billionaire Athina Roussel Onassis, one of world's richest women, got married to an Brazilian equestrian star in Sao Paulo Saturday.

The 20-year-old heiress married 32-year-old Alvaro Affonso de Miranda in a lavish ceremony on the grounds of an art museum.

Some 750 guests attended the wedding, along with 400 private security guards hired to keep out reporters and photographers.

Ms. Onassis was to wear a dress by designer Valentino.

The bride is the granddaughter of the late Greek shipping tycoon Aristotle Onassis. Media reports say she inherited an empire worth between $1 billion and $3 billion on her 18th birthday.

The reports say the bride's father Thierry Rouseel, who has fought his daughter over control of the fortune, did not attend the wedding.

Some information for this report provided by AP and Reuters.