Prince William has just been given a $685-year-old estate that is worth $1 billion.
The £16.5 billion Crown Estate ($19 billion) is the most important part of the family's fortune.
In return for a portion called the Sovereign Grant, the monarch gives the government overall profits from the estate under an arrangement that dates back to 1760.
Because of the line of succession, Prince William is now the first in line for the British throne. He is a wealthier man.
The private Duchy of Cornwall estate is passed to the future king by his father.
The duchy owns a sprawling portfolio of land and property covering almost 140,000 acres, most of it in southwest England.
According to the accounts of the last financial year, the estate was created by King Edward III in 1337.
It is estimated that it is worth approximately £1 billion ($1.2 million)