At the end of March King Abdullah of Saudi Arabia appointed one of his younger half-brothers, Prince Nayef, second deputy prime minister. As the King himself is prime minister and his younger brother, Crown Prince Sultan, is first deputy prime minister, this has been interpreted as a sign that Prince Nayef will be the next Crown Prince.
Their father, King Abdul-Aziz ibn Saud, was believed to have fathered 37 sons by 16 wives, and since his death in 1953 the throne of Saudi Arabia has passed from brother to brother among his sons. King Abdullah is the fifth son so far to sit on the throne, which he inherited on the death of King Fahd in 2005.
The King is now believed to be 84 years, while the Crown Prince is 82 and suffering from cancer. According to analysts this means that Prince Nayef, said to be born in 1933, could be King of Saudi Arabia sooner rather than later.
More details in an article in The Guardian today: