1720

1720 was a leap year in the Gregorian calendar, occurring during the early 18th century a period of rapid commercial expansion, imperial competition, and reformist thinking across Europe and its colonies.

In finance, 1720 is remembered for sharp bursts of speculation and sudden reversals. The South Sea Company bubble in Britain reached a peak and then collapsed, triggering a nationwide financial crisis that led to the Bubble Act, which sought to curb risky joint-stock ventures. In France, John Law’s Mississippi Company experienced a rapid ascent and a dramatic fall in 1720–1721, illustrating the era’s volatile attitudes toward paper money and colonial speculation. The episode contributed to a broader European reassessment of financial regulation and government oversight.

Diplomatically, the War of the Quadruple Alliance concluded in 1720 with the Treaty of The Hague. The settlement ended hostilities among major European powers and helped redraw the balance of power after years of conflict, with implications for the Mediterranean and Iberian regional order.

Public health also marked the year, as the Great Plague of Marseille began in 1720. The outbreak persisted into 1722, killing tens of thousands and prompting quarantines, evacuations, and public health measures that reverberated through French and neighboring communities.

These events—financial volatility, a major diplomatic settlement, and a deadly epidemic—characterize 1720 as a year of significant upheaval and policy learning in the early modern Atlantic world.