First Lord of the Treasury
Originally three houses, Number 10 was offered to Sir Robert Walpole by King George II in 1732. Walpole accepted on the condition that the gift was to the office of First Lord of the Treasury. The post of First Lord of the Treasury has, for much of the 18th and 19th centuries and invariably since 1905, been held by the Prime Minister. Walpole commissioned William Kent to join the three houses and it is this larger house that is known as Number 10 Downing Street.