Labour won the 1964 general election with a narrow majority of four seats, and Wilson became Prime Minister, the youngest person to hold that office since Lord Rosebery 70 years earlier. During 1965, by-election losses reduced the government's majority to a single seat; but in March 1966 Wilson took the gamble of calling another general election. The gamble paid off, because this time Labour achieved a 96-seat majority over the Conservatives, who the previous year had made Edward Heath their leader.