Original: 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.
Simplified: On June 28 1914, the heir visited the Bosnian capital, Sarajevo. Bosnian Serb militants of the group Mlada Bosna attacked Franz Ferdinand's convoy and assassinated him.