“Cause-in-fact” is a common law doctrine used to determine the scope of legal liability in accident cases. In summary, judges apply a counterfactual “but-for” test to determine whether event x was a necessary or “legal” cause of outcome y; in other words, “but-for event x, outcome y would not have happened”. This test can also be extended to historical events. By way of example, on this day (28 June) in 1914, Archduke Franz Ferdinand of Austria and his wife Sophie, Duchess of Hohenberg (pictured below, left), were assassinated in Sarajevo, the capital of the Austro-Hungarian province of Bosnia and Herzegovina. (The perpetrator of this heinous act was 19-year-old Gavrilo Princip, a member of Young Bosnia and one of a group of assassins armed by the Black Hand, a secret military society formed in 1901 by a group of army officers in the then-Kingdom of Serbia.) The assassination of Ferdinand and Sophie became the casus belli of the Central European conflict that eventually expanded to become the First World War.