 Napoleon promised to send two hundred thousand soldiers to help one hundred thousand soldiers from Piedmont-Sardinia to force the Austrians out of northern Italy; in return, France would receive the county of Nice and Savoy provided that their populations would agree in a referendum.It was the Emperor Franz Joseph, growing impatient, who finally unleashed the war.On 23 April 1859, he sent an ultimatum to the government of Piedmont-Sardinia demanding that they stop their military preparations and disband their army.