Austria-Hungary Declares War on Portugal
The deaths of Franz Joseph's brother, Maximilian (1867), and only son, Rudolf, made the Emperor's nephew, Franz Ferdinand, heir to the crown.
On June 28, 1914, he visited the Bosnian capital, Sarajevo, where Bosnian Serb militants of the nationalist group Mlada Bosna, supplied by the Serbian militant group Black Hand, ambushed Franz Ferdinand's convoy and assassinated him. There were a few members of the Black Hand in Sarajevo that day. Before Franz was shot, somebody had already tried to kill him and his wife. A member of the Black Hand threw a grenade into the vehicle but Franz managed to push it away. It injured some people nearby and Franz made sure they were seen to before the convoy could carry on. Gavrilo Princip was the man who shot and killed Franz Ferdinand and his wife Sophie. The convoy took a wrong turn into a street where Gavrilo Princip was. He took out a pistol from his pocket and shot Franz and his wife.
Wikipedia: World War I
Wikipedia: Portugal In World War I