PRINCE ALBERT II of Monaco – the son of Prince Rainier III and Grace Kelly – begins a three day state visit to Ireland today, along with his fiancee, the 32-year-old South African Olympic swimmer, Charlene Wittstock.

During their stay in the capital, the monarch – who used to be known as the ‘playboy prince’ – will have meetings with the President Mary McAleese, Taoiseach Enda Kenny and Environment Minister Phil Hogan, the royal website reveals.

The couple will also travel to the Marine Institute in Oranmore, where he hopes to initiate scientific co-operation with the Oceanographic Museum of Monaco.

In honour of their visit, here are five things you might not have known about the colourful – and troubled – Monegaseque Princely family.

1. Charlene isn’t the only Olympian in the family tree…

• Prince Albert himself competed in the bobsled at every Winter Olympics from Calgary to Salt Lake City. But he was just following in a healthy family tradition: his maternal grandfather – Grace Kelly’s father, Jack Kelly Snr – who was the child of Irish immigrants from Newport in Mayo, was a triple Olympic gold medal winner in rowing. And Grace’s brother – Albert’s uncle – John B. Kelly Jnr (who was known as ‘Kell’) was also a four-time Olympian in rowing.

2. The younger generation of Grimaldis is much more accessible than the older generation

• When he married Irish-American actress Grace Kelly, Prince Rainier was determined to make her completely his. He laid down a list of strict rules for visitors, which included no autographs; no photographs; no audio recording devices, and nobody was allowed to leave the room unless and until Princess Grace left first.

3. The future King’s speech wasn’t always so fluent

• Like George VI, who is the subject of the Oscar-winning The King’s Speech, Albert II suffered from a stammer for many years, which he claims to have cured through his love of sports.

4. Scandal has dogged the family…

• Albert, who is 53, has never been married before, but has two children – eight-year-old Alexandre Coste, whose mother is an air hostess from Togo, and 19-year-old Jazmin Grace Grimaldi, whose mother is an American real estate agent.  Albert confirmed that 22-month-old Alexandre was his son six days before he was enthroned on 12 July 2005, and announced the paternity of his then 14-year-old daughter the following year. Neither child is in the line of succession to the throne, but they will be entitled to their share of his $1 billion fortune.

• Albert’s sister, Princess Caroline, appeared the most responsible of the three siblings – until she married a Parisian boulevardier 17 years her senior in 1978, against her parents’ wishes. The marriage last two years, although it took the princess another 12 to obtain an annulment from the Vatican which rendered her subsequent children legitimate.

• Albert’s sister, Princess Stéphanie – whom Grace called her “wild child” – took many years to recover from her mother’s death, saying “everyone wanted her to survive, and instead I did.” She had a relationship with a convicted sex offender in the US, before beginning a relationship with her bodyguard Daniel Ducruet, which resulted in the birth of two children, Louis and Pauline. They married in 1995 and divorced just over a year later when he was photographed in a naked embrace with Miss Topless Belgium. Stéphanie gave birth to her third child, Camille in 1998, but declined to name the baby’s father – who was widely rumoured to be another bodyguard. She had a relationship with an elephant trainer, before marrying Portuguese circus artist, Adans Lopez Perez, in September 2003 – and divorced him just over a year later.

• In 1975, Albert’s uncle - John B. Kelly Jnr‘s bid for the mayorship of Philadelphia was derailed after a must publicised fling with a transsexual named Rachel Harlow (formerly Richard Finnocchio.)

5. And so has tragedy

• Legend has it that the Grimaldi family was cursed in the 13th century, when the first Prince Rainier kidnapped and raped a beautiful maiden, who cursed the family, saying “never will a Grimaldi find true happiness in marriage.”

• Grace Kelly, Albert’s mother, died on 14 September 1982, just two months before her 53rd birthday, after she suffered a stroke while she was driving her daughter, Stéphanie, home to Monaco. Stéphanie suffered a serious cervical fracture in the accident.

• Caroline’s husband of seven years, Stefano Casiraghi, died while defending the World Offshore Powerboat Championship in 1990, leaving his wife crippled by grief and unable to perform an public functions for five years. By 1996, she was back in the spotlight – on the arm of “happily married”, Prince Ernst of Hanover, the husband of her long-time friend. They are now married with a daughter.

• John B. Kelly Jnr died of a heart attack while he was out jogging at the age of 57, after his customary morning row.

In pictures: Monaco’s royal family