Pierre Casiraghi, Prince of Monaco, made headlines over the weekend for a bar fight that landed him in the hospital and his alleged assailant in court. Stavros Niarchos III, his wealthy friend who also suffered a blow to the face, may have gotten less attention but is an equally interesting character in his own right.

Niarchos, the grandson of the legendary Greek shipping tycoon who has dated celebrities like Paris Hilton and Mary-Kate Olsen, was with the Prince of Monaco at the trendy Double Seven bar in New York's Meatpacking District when he got involved in a melee with former nightclub owner Adam Hock.

Hock, 47, claimed that the prince, Niarchos, and two others approached him and was harassing the models he was with before grabbing a $500 bottle of vodka from his table, the New York Post reported.

Then a bloody, boozy brawl ensued. Hock allegedly punched Casiraghi, Niarchos and a couple of others. Casiraghi was so bashed up, he was taken to New York Presbyterian/Weill Cornell Medical Center and released later Saturday, sources tell the Post.

Hock was charged with four counts of third-degree assault.

Some witnesses told the paper the young men were being obnoxious and Hock's lawyer called them trust-fund babies who think the world is owed to them, but friends of Casiraghi claimed Hock instigated the altercation and Niarchos was just trying to rescue his friend.

The prince walked up to the table, and Adam just slammed him for no reason, the witnesses said. Stavros jumped in to help Pierre, and then he go slammed in the face.

Niarchos, 26 years old and an heir to his family's $2 billion fortune, was with his Australian model girlfriend Jessica Hart when the fight broke out. According to TMZ, he is the eldest son of Philip Niarchos, son of legendary shipping tycoon Stavros Niarchos Sr., and Victoria, an Irish and Greek member of the Guinness beer clan. He was born in New York and grew up in Paris.

The shipping heir appears to have very different interests than his grandfather. He graduated from the University of Southern California film school in 2007 is better known for his flings with Mary-Kate Olsen, Lindsay Lohan and Paris Hilton.

Niarchos has developed the reputation of being quite the heart-breaker. Olsen told W magazine that she was crushed when he left her for Paris Hilton in 2005. It's a hurtful and painful subject, she told the magazine, according to Softpedia.

Hilton and Niarchos split a year later, according to People. Olsen and Niarchos were spotted canoodling in 2007, sparking short-lived rumors that the two were back together.