Around 9:40 a.m., as churches filled for All Saints' Day mass, the ground shook for nearly six minutes. Candles toppled and set the wooden city ablaze, while a tsunami surged up the Tagus River, drowning survivors who had fled to the waterfront. Between 30,000 and 50,000 people died. The disaster reshaped European thought, prompting Voltaire's skepticism in Candide and Immanuel Kant's early writings on seismology.
The Marquis of Pombal, King Joseph I's chief minister, took charge of the response with a famously terse directive: 'What now? Bury the dead and feed the living.' He organized firefighting crews, price controls to prevent profiteering, and one of history's first systematic disaster surveys, sending questionnaires to every parish asking how long the shaking lasted and whether animals behaved strangely beforehand.
The rebuilding that followed transformed Lisbon into a grid of wide, earthquake-resistant streets in the Baixa district, using a technique now called the 'Pombaline cage'—a lattice of timber designed to flex rather than collapse. Engineers tested building models by marching troops around them to simulate tremors.
The catastrophe rippled through European philosophy. It struck on a major religious holiday, destroying nearly every church in the city while sparing the red-light district, a detail that scandalized theologians defending divine providence. Voltaire seized on this irony in Candide, and the event is often cited as a turning point that pushed Enlightenment thinkers toward more secular, empirical explanations of natural disaster.
Key people: Sebastião José de Carvalho e Melo, Marquis of Pombal, King Joseph I of Portugal