Guglielmo Oberdan was an Italian irredentist. He was executed after a failed attempt to assassinate Austrian Emperor Franz Joseph, becoming a martyr of the Italian unification movement.

Italian irredentism was a political movement during the late 19th and early 20th centuries in Italy with irredentist goals which promoted the unification of geographic areas in which indigenous peoples were considered to be ethnic Italians. At the beginning, the movement promoted the annexation to Italy of territories where Italians formed the absolute majority of the population, but retained by the Austrian Empire after the Third Italian War of Independence in 1866.