What happened September 1864 AD

On 3 September 1864, a shed used for preparation of nitroglycerin exploded at the factory in Heleneborg, Stockholm, killing five people, including Nobel's younger brother Emil.

Victor Emmanuel sought a safer means to the acquisition of the remaining Papal territory. He negotiated with the Emperor Napoleon for the removal of the French troops from Rome through a treaty. They agreed to the September Convention in September 1864, by which Napoleon agreed to withdraw the troops within two years.