Prince Albert and Princess Charlene Mourn the Shocking Death of His Young Cousin, 29

Prince Albert’s Cousin Found Dead in Monaco GardenODD ANDERSEN - Getty Images

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A member of Monaco’s royal family has died after being found in a public garden on Sunday. Antoine de Massy, 29, was the grandson of Princess Antoinette, the older sister of the late Prince Rainier III. That made Antoine a first cousin once removed of Rainier’s son, Prince Albert II, the principality’s reigning sovereign.

“Their Serene Highnesses Prince Albert II and Princess Charlène learned with sadness of the death of Antoine de Massy, aged 29, grandson of Princess Antoinette, the elder sister of Prince Rainier III,” the Prince’s Palace said in a statement. “Their Highnesses share in the grief of his family and loved ones and extend their sincere condolences at this painful time.”

Princess Antoinette, Princess Caroline, Prince Albert, and Princess Stéphanie at Prince Rainier’s funeral in 2005.ERIC GAILLARD - Getty Images

The statement also noted, “Passionate about tennis, he was part of a family history closely linked to the sport in the Principality.” Antoine began playing at age three, introduced by his father. He later moved to Florida to train while in school, and he said he hoped to represent Monaco at the Olympics. Antoine told Vogue Italia in 2012 that his dream was “to become number one in the world,” adding, “Even in the top 20 wouldn't be bad!” His aunt, Elizabeth-Ann de Massy, led the Monte-Carlo Country Club and the Monegasque Tennis Federation until her death in 2020. Her daughter, Mélanie-Antoinette de Massy, now runs both as well as the Rolex Monte-Carlo Masters.

Elizabeth-Ann de Massy (center) with Prince Albert and Rafael Nadal at the 2017 Monte-Carlo ATP Masters.YANN COATSALIOU - Getty Images

Mélanie-Antoinette de Massy (right) with Albert, Charlene, Jannik Sinner, and Carlos Alcaraz at the 2026 Monte-Carlo Masters.Jean Catuffe - Getty Images

Local newspaper Monaco-Matin reported on Monday that a relative grew worried when Antoine missed a family lunch Sunday and went to Monaco’s Public Security department. Antoine was found hours later in a garden behind Villa Sauber, a cultural landmark and one of the last Belle Epoque villas in Monaco. Police also reviewed security camera footage and identified a person near the scene, who was later arrested and was still in custody on Monday evening. But officials have not said if the person is a suspect. Monaco’s prosecutor general told the paper an investigation had been opened “to determine the cause of death.”