Sidónio Pais was a prominent Portuguese politician who served as the President of Portugal from 1918 until his assassination. His presidency was marked by vigorous efforts to stabilize the country amidst political strife following the First World War. The rise of his authoritarian regime was triggered by a coup that he led in 1917, which had optimistic beginnings but turned dark as political opposition began to grow. His rule became increasingly contentious, with many accusing him of suppressing dissent and undermining democracy. On December 14, 1918, this mounting discontent reached a violent conclusion when Pais was assassinated in Lisbon by a former army officer named Afonso Costa. The attack took place as Pais was leaving the Camões Theater, and he was shot multiple times. Despite attempts to save him, he succumbed to his injuries shortly thereafter.

The aftermath of Pais’ assassination threw the country into further political chaos. His death opened the door for rival factions to vie for power, leading to a turbulent period in which various political movements emerged, competing for influence in a fractured political landscape. This era would eventually lead to the establishment of the Portuguese Republic more firmly, but at the cost of years of instability and multiple changes in government. The event highlighted the severe divisions within Portuguese society and politics during the tumultuous years following the end of World War I.